FM 21-40 
*c i 
BASIC FIELD MANUAL 
DEFENSE AGAINST CHEMICAL ATTACK 
Changes 1 
No. 1 (' 
WAR DEPARTMENT, 
Washington 25, D. C., 11 September 1943. 
FM 21-40, 7 September 1042, is changed as follows: 
The following new and changed symbols for chemical agents 
I -eferred to in this manual are listed below. These symbols will 
j ,e corrected wherever they occur in the manual. 
Symtol 
Agent Old New 
Lewisite M-l L 
Mustard gas HS H 
Mustard-lewisite mixture MS HL 
Brombenzylcyanide CA BBC 
Arsine , ■ SA 
Hydrocyanic acid AO 
The following is added to the table, Vesicants, page 10. 
NAME AND SYMBOL NITROGEN MUSTARDS (HN) 
Odor Faint odors varying from fishy or soft-soaplike to prac- 
tically odorless. 
Color and state in field Varying from liquids to low melting solids, colorless to 
pale yellow. 
Effects on body Vesicant, blisters skin. Vapors only about one-fifth 
as damaging to skin as equal concentrations of ordi- 
nary mustard gas; liquids blister more rapidly but 
less severely than equal amounts of ordinary mustard 
gas. Damage to eyes varies according to kind used; 
all will damage eyes both as vapor and liquid. Dif- 
*The individual items in this change will be cut apart and pasted 
over the specific paragraphs or subparagraphs affected. This change 
supersedes section II, Training Circular No. 3, and section I, Training 
Circular No. 67, War Department, 1942 ; and Training Circular No. 51, 
War Department, 1942. 
551503° -43 1 BASIC FIELD MANUAL 
NAME AND SYMBOL NITROGEN MUSTARDS (HN) 
fering from other vesicants, the vapors produce 
serious eye casualties, at concentrations too low to be 
detected by odor or irritation. All are highly toxic 
by inhalation, the concentrations required for lethal 
effect varying from less than, to three times, that of 
ordinary mustard gas. However, the least toxic is 
also the most volatile, so it may be just as damaging 
in the field as the more highly toxic ones. Systemic 
poisoning, affects nervous system. 
First-aid treatment Remove contaminated clothing, wash skin with soap 
and water, or apply protective ointment and wash 
with water. If liquid enters eye, flush with water. 
All first aid must be effected as quickly as possible. 
Persistency Varies from one-fifth of mustard gas to much more than 
ordinary mustard gas. 
Action on food and water._. Renders unprotected food and water unfit for use. The 
senses are unreliable to detect contamination. 
Action on metals.. Slight. 
How used For casualty effect or to deny ground through threat r 
casualties. Probably disseminated by same mea. 
used for ordinary mustard gas. 
Protection required. Gas mask and protective clothing. Eye-shields and 
individual protective covers against spray. 
The following is added to the table, Screening smokes (page 14). 
NAME AND SYMBOL TITANIUM TETRACHLORIDE (FM) 
Odor Acrid. 
Color and state in field.,, 1. Dispersed as a liquid which changes to white smoke 
upon contact with air. 
Effects on body Liquid burns. Also strong acid; vapor and smoke 
irritating to throat. 
First-aid treatment None necessary for smokes; for liquid agent, wash 
affected parts with water and then -with soap and 
water. 
Action on food and water... Liquid makes food and water unpalatable but not toxic. 
Action on metals. Some corrosion by the smoke; none by liquid on steel, 
if dry; vigorous corrosion if moist. 
How used In airplane spray for screening; in artillery shell, mort ar 
shell, and, for training, in cylinders to simulate cloud 
gas. 
Protection required Gas masks, in heavy concentrations. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) DEFENSE AGAINST CHEMICAL ATTACK 
7. Chemical Agents. 
6. Vesicants. 
(2) Lewisite (L) .—Lewisite, colorless in * * * threat of 
casualties. It is dispersed by the same means as mustard gas 
and is very effective when sprayed from an airplane. The 
greatest danger to personnel in a spray attack of lewisite is 
that of getting drops in the eyes. This will result in almost 
instant injury and later permanent blindness unless eye 
ointment M—1 (or BAL) or eye solution M—1 is applied to 
the eyes quickly. Headache, violent coughing and sneezing, 
and possibly vomiting will be the result of a few breaths 
of a high concentration of lewisite vapor following an air- 
plane spray attack. Nearly odorless in * * * corrosive to 
metals. For cold weather spraying, mixtures of lewisite with 
mustard gas (HL) in varying proportions will produce solu- 
tions with lower freezing points than either of the agents 
singly. 
(3) Nitrogen mustards (HN) (added).—Nitrogen mustards 
vary from liquids to low melting solids, are colorless to pale 
yellow, and have faint odors varying from fishy or soft-soap- 
like to practically odorless. Because of this lack of pro- 
nounced odor, personnel may, without being aware of the 
presence of a chemical agent, undergo exposure which will 
produce eye and respiratory casualties. As in the case of 
lewisite, the great danger from a spray attack is serious in- 
jury caused by getting drops in the eyes. Their volatility 
varies from much less to five times greater than that of or- 
dinary mustard gas (H). Nitrogen mustards hydrolyze very 
slowly in water. The hydrolysis is not complete except in 
water containing alkali (pH above 7-8), and even then ele- 
vated temperatures must be used to get noticeable rates of 
hydrolysis. The products of hydrolysis are relatively harm- 
less. The nitrogen mustards vary greatly in toxic effects. 
They vary greatly in power to damage the eyes. The less 
volatile members are much less effective than equal concen- 
trations of ordinary mustard gas vapor, while the more vol- 
atile members produce damage to the eyes equal to or greater BASIC FIELD MANUAL 
than that produced by a similar mustard gas exposure. Al- 
though flushing the eyes with water is effective in the case 
of liquid nitrogen mustards, there is no satisfactory first-aid 
measure for eye injuries from the vapor. The more volatile 
members in liquid form damage the eyes more severely than 
ordinary liquid mustard gas. The less volatile members dam- 
age the respiratory tract to about the same degree as an 
equal concentration of mustard gas vapor, but because of 
their low volatility may be less dangerous in the field than 
mustard gas. The most volatile member is only one-third as 
effective on the respiratory tract as is mustard gas vapor of 
equal concentration, hut because of its great volatility a heavy 
field contamination may be as dangerous to the respiratory 
tract as a similar mustard gas contamination. The vapors 
are only about one-fifth as damaging to the skin as an equal 
concentration of ordinary mustard gas vapor. The liquids 
blister the skin more rapidly, but less severely, than equal 
amounts of ordinary mustard gas. 
f. Screening smokes. 
(1) Sulfur trioxide solution (F8).—A solution of * * *• 
30 to 60 seconds. 
(1V2) (Added.) Titanium tetrachloride (FM).—Titanium 
tetrachloride is a liquid smoke agent. It is employed for the 
same purposes and dispersed in the same ways as FS. It is 
less corrosive than FS, and its vapors and smoke are irritat- 
ing to the throat. 
(2) HC mixture.—This consists of * * * grayish-white 
smoke. Screens are developed by various size smoke pots, for 
training purposes; grenades, floating smoke pots, and artil- 
lery shells for combat purposes. The obscuring value * * * 
sometimes more desirable. Its fumes are noninjurious to fab- 
rics or metals. 
(4) (Added.) Precautions.—Screening smokes consist of finely 
divided solid particles or liquid droplets suspended in the atmos- 
phere. The suspended material may consist of metallic salts, me- 
tallic oxides, inorganic acids, hydrocarbons, and other materials. 
Any of these substances may be injurious if heavy conceutra- DEFENSE AGAINST CHEMICAL ATTACK 
tions are breathed for relatively long periods of time. There- 
fore if personnel must remain close down wind from smoke 
generators, gas masks should be worn to assure adequate pro- 
tection. It is estimated that the maximum allowable exposure 
should be not more than 10 minutes within a distance of 10 
yards of the generators if the gas mask is not worn. Since 
some individuals are more sensitive than others to these agents, 
gas masks should be worn if unpleasant effects are noticed. 
Screening smokes should not be released in inclosed spaces 
where heavy concentrations may result. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
8. How to Test for Odors. 
a. Set, Oas Identification, Instructional, MI. 
(3) Method of testing. 
(c) There is no danger associated w*ith identifying chemical 
agents prepared in this way, provided that proper precautions 
are taken to prevent the activated charcoal from coming into 
contact with the person or clothing. The best results * * * 
gas reconnaissance detachments. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
9. General First-Aid Measures. 
e. Lung irritants. 
3. (Superseded.) Disposition of personnel.—During the pe- 
riod following exposure, and prior to development of symptoms, 
the disposition of personnel exposed to lung irritant agents is 
a command decision. The unit commander will decide whether 
such personnel shall receive prescribed first aid measures and 
be evacuated, or continued in action. The commander will 
base his decision on the tactical situation, the severity of ex- 
posure of personnel as known to him, and the recommenda- 
tions of the medical officer. 
(4) (Superseded). First aid.—If unmasked the mask should 
be adjusted while gas is present in the area. The mask should 
be removed as soon as the area is clear of gas. Ordinarily, BASIC FIELD MANUAL 
removal of personnel from the gassed area is neither necessary 
nor desirable. The clothing of the affected individual should 
be loosened, and the man kept completely still, relaxed, and 
warm with blankets. Nonalcoholic stimulants such as hot 
coffee or tea may be given. This type casualty should be 
evacuated on a litter to an aid station as soon as possible. 
i. First aid for vesicant casualties. 
(1) Eyes.—First aid for vesicants in the eyes consists of 
washing them freely and as quickly as possible with water 
from the canteen. This washing should * * * an aid sta- 
tion. If the agent can be identified as lewisite, eye ointment 
M—1 (or BAL) or eye solution M—1 will be used instead of 
washing. The eye can be most effectively irrigated by an- 
other man, but in the absence of immediate help, the indi- 
vidual must attempt to flush his own eye without delay. 
This is best done with the victim lying on his back, face up, 
and shielded from the ground by his protective cover. The 
injured eye is pulled open by traction on the lower lid with 
one hand, and water is slowly poured into the eye from the 
canteen held close to the eye with the other hand. The eye 
should be moved from side to side, and up and down, during 
the washing, which should be continued for about 5 minutes, 
if sufficient water is available. In vapor contamination of 
the eyes by nitrogen mustards the damage has already been 
done, and it is too late for effective removal of the agent. 
However, if a kit, first-aid, gas casualty, is available (on a 
combat or motor vehicle), item No. 4, eye and nose drops, 
may be used for the relief of eye or nasal pain. 
(3) Skin (Superseded).— (a) General.—In many instances 
there is a delay of some hours between the time when the 
chemical agent comes into contact with the individual and the 
time when he develops recognizable signs of injury. 
(&) Mustard gas.—If liquid mustard gas is discovered on an 
individual’s clothing, the contaminated spots will be cut from 
the clothing, or if grossly contaminated, the clothing should be 
551593°—43 2 DEFENSE AGAINST CHEMICAL ATTACK 
removed. If vapor is encountered while' wearing nonimpreg- 
nated clothing, the clothing should be removed as soon as prac- 
ticable. If impregnated clothing is worn it need not be 
removed. Soap and water will remove some of the poisonous 
vapor of the agent from the skin. If liquid has reached the 
skin, it should be blotted with ointment wrapping, dry gauze, or 
cloth. The protective ointment M4 is then rubbed thoroughly 
upon the affected area and the excess removed with a clean 
cloth. If this ointment is not available, bleaching powder or 
paste may be used. If bleaching powTder or protective ointment 
is not available, the liquid agent may be removed by dabbing 
with a dry cloth. The skin should then be washed with soap 
and water. When bleaching powder is used, the most effective 
method of its application is to make a paste of a small quantity 
of the powder with water, the mixture being carefully stirred 
while being prepared. Usually equal volumes of water and 
powder are used. The contaminated area of skin is covered 
as well as the immediately surrounding area. The paste is 
rubbed in well for about 1 minute and then removed after not 
more than B minutes by flushing with a large quantity of water, 
if available. A subsequent bath with soap and water is desir- 
able. Care must be taken not to get bleaching powder paste 
into the eyes. If the skin has already begun to show definite 
redness or blisters, the bleaching powder or protective ointment 
should not be used, as it is irritating. 
(c) Nitrogen mustards.—If the liquid agents have contam- 
inated the skin, protective ointment should be used as for other 
vesicant agents. Since the ointment merely dilutes and does 
not destroy nitrogen mustard, it is necessary as a final step to 
wash off the film of ointment with water, or preferably with 
soap and water. If the contamination is positively known to 
be due to nitrogen mustard, soap and water should be used for 
decontamination, but it is safer where doubt exists to use first 
the protective ointment, followed by soap and water or plain 
water. If reddening of the skin has appeared, the use of the 
ointment should be omitted and soap and water alone used. 
Blisters should not be opened until medical treatment is avail- 
able. In vapor contaminations, the damage has already been 
done, and it is too late for effective removal of the agent. How- 
ever, if a kit, first-aid, gas casualty, is available (on combat or 
7 BASIC FIELD MANUAL 
motor vehicle), item No. 6, pontocaine compound ointment, may 
be used to allay the irritation and itching of the skin. 
(d) Lewisite.—Both the liquid and vapor of lewisite are 
highly vesicant, producing grayish discoloration, followed by 
blisters. Being a compound of arsenic, it is most important 
that first-aid measures be applied immediately, as serious ar- 
senical poisoning may result from the absorption of arsenic 
through the skin. Contaminated clothing should be immedi- 
ately removed and the bulk of the liquid lewisite blotted from 
the skin with cotton waste or cloth. After removal of con- 
taminated clothing and liquid lewisite, the following first-aid 
measures may be used: 
1. Protective ointment.—,The protective ointment is ef- 
fective in the treatment of liquid lewisite drops, 
provided the bulk of the liquid is blotted from the 
skin immediately after contact. The use of the 
ointment will lessen the lewisite burn if applied 
immediately. 
2. Hydrogen peroxide (8 percent).—If available, the use 
of hydrogen peroxide is recommended. The hydro- 
gen peroxide should be applied freely to the place 
contaminated with lewisite after the bulk of the 
agent has been blotted off with a cloth. 
3. Soap and water.—Soap and water are more effec- 
tive than water alone or a wet cloth. 
4- Blisters should be protected from breaking. 
k. Systemic poisons. 
(1) Hydrocyanic acid. 
(&) (Superseded.) First aid.—The individual’s mask should 
be properly adjusted and left on as long as the area is contami- 
nated with gas. If the patient is not breathing, prompt artificial 
respiration should be given until medical aid is available. If in a 
closed space such as a room, dugout, tank, or pillbox, it. is advis- 
able to get into fresh air, as too great a concentration of hydro- 
cyanic acid may penetrate the canister of the mask. If a kit, 
first-aid, gas casualty, is available (on a combat or other motor DEFENSE AGAINST CHEMICAL ATTACK 
vehicle) item No. 7, amyl nitrite, should be used. One ampule is 
removed from the carton and crushed in its woven jacket with the 
fingers. This is held close to the victim’s nose and mouth, or 
thrust inside the gas mask facepiece. This procedure may be re- 
peated three times at 3- to 5-minute intervals, meanwhile con- 
tinuing artificial respiration until the victim breathes natu- 
rally. Keep the patient warm but out of the direct rays of 
the sun. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) BASIC FIELD MANUAL 
Chapter 5 
USE AND CARE OF INDIVIDUAL PROTECTIVE 
EQUIPMENT 
LIGHTWEIGHT SERVICE MASK 
Section II % (Added) 
■ 91.1. Description.—The lightweight service mask differs 
from the older service mask in that it consists of a lighter 
canister (M10), a shorter hose, and the use of the M3 face- 
piece, which contains a nosecup in contrast to the M2 face- 
piece, now in common use. 
■ 91.2. Carrying of the Mask.—The lightweight service 
mask may be slung in several positions, the most favorable of 
these being chosen to fit the occasion and the equipment car- 
ried. The positions of carry are gas alert, hack carry, and 
side carry. In the gas alert position, where the mask is 
most readily available for use, the carrier is slung in front 
of the body on the chest. This position is favorable for driv- 
ers and occupants of motor vehicles (fig. 49.1(D). It is one 
of the two positions of carry at which the facepiece can be 
worn. The hack carry in one modification is suitable for In- 
fantry, Medical Department, and other units carrying the 
pack (fig. 49.1®). In another modification the hack carry is 
satisfactory for Cavalry and units when the pack is not worn 
(fig. 49.1@). The facepiece can be worn at the hack carry 
only if the pack is also worn (fig. 49.2®). The side carry for 
general use may be modified by sliding the mask to the back, 
of the left hip or to the front for carrying in the lap when 
seated (fig. 49.1® and ®). The facepiece can be put on with 
the carrier at the side carry, but this position is not satisfac- 
tory while the facepiece is being worn; the carrier must be 
brought up to the gas alert (fig. 49.2® and ® ). 
a. To sling carrier at gas alert.—The command is: 1. gas 
alert, sung, 2. MASK. At the command mask, hold the carrier 
by shoulder strap in the left hand, the flap of carrier facing 
away from the body (fig. 49.1®). With both hands, swing 
strap over the head, at the same time passing left elbow through 
loop to position at side (fig. 49.1©). 
551593°—43 3 DEFENSE AGAINST CHEMICAL ATTACK 
TWO. Shorten shoulder strap hy hooking harness snap into 
D-ring at carrier (fig. 49.1®). The carrier is then in position 
at an angle on the left side of the chest. (See note 1.) Adjust 
the body strap to pass around the body and fasten to the small 
D-ring at bottom of carrier (fig. 49.1® and ®). (See note 2.) 
b. To sling mask at back carry.—The command is: 1. back 
carry, song, 2. MASK. At the command mask, the first count is 
the same as for the gas alert carry. 
TWO. Shorten strap by hooking harness snap into D-ring at 
carrier (fig. 49.1®). Slide carrier around under the left arm 
to position on the back (fig. 49.1®). Adjust the body strap 
around equipment and fasten to the sliding D-ring pn the shoul- 
der strap (tig. 49.1@). (See notes 1, 2, and 3.) 
c. To sling mask at side carry.—The command is: 1. side 
carry, song. 2. MASK. At the command mask, the first count 
is the same as for the gas alert carry. 
TWO. Allow the shoulder strap to remain extended. Adjust 
the body strap to pass around the body and fasten to the small 
D-ring at bottom of carrier. Place carrier at left side (fig. 
49.1@). If desired, slide the carrier to the back of the left 
hip or to the front for carrying in the lap (fig. 49.1® and ®). 
d. To move carrier from one carry position to another.—The 
command for the new position is given in the same manner as 
if carrier were unslung. For example, from back carry to gas 
alert carry, the command is: 1. gas alert, sling. 2. MASK. 
Unfasten body strap, move carrier to new position, and refasten 
body strap as prescribed for position assumed. 
e. To unsling mask.—The command is : 1. unsling, 2. MASK. 
Unfasten body strap. Unfasten harness snap on shoulder strap 
if snap is in use. With both hands, grasp shoulder strap and 
raise and slide over the head. Hold the shoulder strap in left 
hand with the flap of carrier away from body (fig. 49.1®). 
Notes.—1. In adjusting the shoulder strap, the shoulder strap slide 
should be adjusted so that the carrier will be about at the waist line. 
The shoulder strap harness snap should be adjusted so that when the 
strap is shortened the carrier will be well up on the chest. 
2. When wearing this mask with full field equipment, the pack is 
slung first and then the mask. 
3. When the mask is slung at back carry with the pack, the carrier 
is positioned at the left of the pack resting against its side and well up. 
(fig. 4fi.l®). Without the pack, the carrier is positioned at an angle 
across the back (fig. 49.1®). 
11 BASIC FIELD MANUAL 
■ 91.3. To Adjust the Mask.—a. (1) The mask being slung, 
the command is: gas. At the command gas, the carrier must 
be moved to the front of the body if not already there. If slung 
at back carry (figs. 49.1® and ®), unfasten body strap and 
slide carrier to front in gas alert position. The shoulder strap 
may be left in either the extended or shortened position. Dis- 
pose of arms, etc. Remove and dispose of head covering (fig. 
49.2®). Open flap of carrier with either hand (tig. 49.2®). 
Grasp the facepiece above the eyepieces with the right hand 
(fig. 49.2®) and remove from the carrier. Grasp facepiece 
with both hands, sliding first the left then the right thumb up 
inside the facepiece at the edge and under the lower and 
middle head harness straps. The fingers are placed straight 
and together on the facepiece almost above the eyepieces (fig. 
49.2®). The thumbs are on the facepiece on the inside (fig. 
49.2®). Bring facepiece up in front of the face. Thrust out 
the chin. (See notes 1, 2, and 3.) 
TWO. Seat chin pocket of facepiece firmly on the chin, holding 
the head stationary. Sweep head harness smoothly over the 
head (fig. 49.2®). Check to make sure all head harness straps 
are straightened out. 
THREE. Close the outlet valve by placing the palm of the 
right hand firmly over the valve and exhale vigorously to clear 
the facepiece of gas (fig. 49.2®). Check the mask by pinching 
the hose near the canister to shut off the air supply (fig. 49.2®). 
Inhale. No air should enter and the facepiece should tend to 
collapse iigainst the face. (See note 4.) 
FOUR. Replace headpiece. Fasten the flap of carrier so 
that the hose comes out at the left or right depending upon the 
position in which the carrier is to be placed (fig. 49.2®). 
(2) If the carrier was previously slung in any position except 
the back carry with pack, it will be placed at the gas alert carry 
(figs. 49.2® and @). The hose should come out at the right 
of carrier. The shoulder strap is shortened, if not already, by 
engaging the harness snap. The body strap is fastened and 
original equipment retaken. 
(3) When the mask has been carried at back carry with the 
pack, it will ordinarily be returned to the back carry. The hose 
should come out at the left of the carrier, the shoulder strap 
is extended by unfastening the harness snap and the carrier 
12 DEFENSE AGAINST CHEMICAL ATTACK 
moved to the rear. Bring the left arm between the hose and 
body. The shoulder strap is again shortened by engaging the 
harness snap (fig. 49.2®). The carrier is brought up in posi- 
tion at the left of the pack so that the hose comes over the left 
shoulder (fig. 49.2 @). The body strap is refastened, around 
the pack, to the sliding D-ring on shoulder strap. (See notes 
5, 6, 7, and 8.) 
Notes.—1. Without the numbers, at the command gas, immediately 
stop breathing. Ability to hold the breath for 30 seconds or more 
under conditions of excitement, should be developed. Do not take 
another breath, even if the breath has just been exhaled, until the 
facepiece is adjusted and cleared. 
2. Dismounted troops armed with or carrying weapons and equip- 
ment will immediately dispose of equipment and free both hands 
without permitting any part of the equipment to touch the ground 
unless absolutely necessary. Mounted troops and animal drivers will 
halt and temporarily free both hands by disposing of the reins in such 
a manner as to prevent the mount or team from bolting. 
3. After disposing of weapons during adjustment of the gas mask, 
pass the head or chin strap of head covering over the left forearm. 
Soft cloth caps and headpieces without head or chin straps will be 
tucked in the waist or cartridge belt or between the carrier and the 
body. 
4. For adjustment without the numbers, resume normal breathing 
as soon as the mask is cleared, seated, and checked. 
5. Headpieces having chin strap which can be unfastened will be 
placed under the chin and refastened, otherwise the chin or head 
strap will be adjusted to the back of the head. 
6. Weapons or equipment will be brought to the original position. 
7. Mounted troops and drivers will dismount and adjust animal 
masks. 
8. When the toque and/or hood are worn, the following modifications 
of gas mask drill are necessary : 
h. To adjust mask.—At the command GAS, dispose of arms, 
etc., and remove headpiece in the following manner: insert thumb 
of right hand between chin strap and cheek, slide thumb down 
and remove chin strap from under chin. Using both hands, lift 
helmet off head with a backward sweep to prevent neckband 
binding. Dispose of helmet by hanging it by the chin strap 
over left arm. If knitted cap is worn, remove it from head and 
place in helmet. If toque and hood are worn, open front and 
push hood off head, letting it hang about neck. If toque has 
front that can be opened around neck, open front and push 
back over head at the same time hood is removed. If toque 
13 BASIC FIELD MANUAL 
does not have front opening, remove and thrust it, neck first, 
over the right arm, extending the right hand through the face 
opening. Remove facepiece from carrier in the usual manner 
and draw it through the face opening of toque and push toque 
down over hose. Place the facepiece on the head and after clear- 
ing the facepiece, put the toque on the head. Replace the hood 
and helmet by unhooking the helmet strap and refastening it 
under chin. 
c. To test for gas.-—If toque and hood do not open, thrust 
the first two fingers of the right hand under the toque and hood 
and pull facepiece away from right cheek. Test for gas as 
described. 
d. To remove mask.—Unhook chin strap of Ml helmet. Using 
both hands, lift helmet off head with a backward sweep. Re- 
fasten chin strap and hang helmet by chin strap over left arm. 
If knitted cap is worn, remove it from head and place in helmet. 
If toque and hood open in front, open and push back off head 
to hang about neck. Remove facepiece and grasp top of face- 
piece with the right hand and carry toque up over facepiece 
and on right arm. Replace facepiece in usual fashion. Replace 
headgear. 
■ 91.4. To Test foe Gas.—The facepiece being adjusted, the 
command is: TEST FOR GAS. Take a moderately full breath, 
exhale part of the air breathed, and stop breathing. Stoop to 
bring the face as close to the ground as possible without touch- 
ing any part of the person or equipment to the ground. Break 
the seal of the facepiece by grasping one of the lower or middle 
head harness tabs near the rivet and pulling the facepiece 
away from the face. This will allow air to enter without 
touching the finger to the skin, since the finger may be dirty 
or contaminated with chemicals. Sniff gently but do not inhale 
(fig. 49.3®). Resume the erect position. Clear the facepiece 
as prescribed in the adjustment for the count of THREE 
(fig. 49.2®). Resume normal breathing. 
Notes.—1. Personnel will be taught to test for gas habitually before 
removing the mask. 
2. If mounted, dismount. 
■ 91.5. To Remove and Replace Mask.—IMPORTANT. The 
mask, if contaminated with chemical agents, must not be re- 
14 DEFENSE AGAINST CHEMICAL ATTACK 
placed in the carrier, but, should be hung up to air or be other- 
wise decontaminated. The mask having been adjusted the com- 
mand is: 1. Remove and replace, 2. MASK. Important: First, 
test for gas as prescribed in paragraph 91.If (fig. 49.3®). (See 
notes 1 and 2.) If no gas is detected, lift the headpiece with 
the left hand, and with the right hand grasp the facepiece 
below the eyepieces (fig. 49.4®). With a downward, outward, 
and upward motion, remove the facepiece. Place in the crook 
of the left elbow or, if carrier is on the back, allow the facepiece 
to hang over the left shoulder. Replace headpiece, using both 
hands (fig. 49.4®). 
TWO. (If carrier is slung at the back, unfasten body strap 
and slide carrier to gas alert carry position.) Grasp facepiece 
with the right hand. Place head harness in facepiece (fig. 
49.4®). Open the carrier with the left hand while steadying 
it with the hand holding the mask (fig. 49.4®). Grasp the 
canister with the left hand and straighten out the canister 
straps. The thumb is on top of the canister with the fingers 
underneath. Loop the hose around the canister lengthwise in 
such a manner that the canister can he placed inside the face- 
piece with the canister inlet valve at the chin of the facepiece 
(fig,. 49.4®). Grip the canister through the facepiece above 
the eyepieces with the right hand and start the hose loop into 
the carrier (fig. 49.4®). 
THREE. Place the mask in the carrier and fasten the flap 
(fig. 49.4®. Return the carrier to the original carrying position 
or to a different position if designated. 
Notes.—1. If wearing a helmet, prepare the headpiece for removal 
by unsnapping the chin strap. 
2. Arms and equipment will be placed in the most convenient way to 
free both hands while removing the mask. If possible, avoid grounding 
arms or equipment. 
■ 91.6. To Check Fit of Mask.—The facepiece being adjusted, 
the command is: 1. check. 2. MASK. At the command mask, 
pinch together the walls of the hose near the canister. Exhale, 
then inhale. No air should enter. (See notes 1 and 2.) The 
outlet valve should permit free escape of air. (See note 3.) 
Notes.—1. To adjust the head harness for a correct fit of facepiece, 
first loosen all six straps. Put facepiece on with straps loose and hold 
firmly against the chin with one hand. Center the head harness pad 
fairly well down on the hack of the head. Adjust the middle pair of 
15 BASIC FIELD MANUAL 
straps by tightening evenly until the buckles lie flat. The ends of the 
straps should be the same length. The straps should clear the top 
of the ears and he just snug, not too tight. Adjust the top pair and 
the bottom pair to the same tension as the middle pair of straps. Check 
mask to test the fit. If the mask does not fit, the top pair may be 
drawn up a bit tighter; or if the individual has prominent hollows at 
the temple, the middle pair may need further adjustment. 
2. If the facepiece allows air to enter at this time, two possible 
faults are indicated ; 
a. If the leakage is noticed between the edges of the facepiece and 
the face, faulty adjustment and fitting are probable. Such a fault may 
be overcome by pressing the edges of the facepiece to the face and 
readjusting head harness by carefully pulling up each of the opposing 
pairs of head harness straps a little at a time. A mask adjusted too 
tightly may cause a channel at the edge of the facepiece through which 
the gas may enter. Headaches and discomfort on prolonged wearing 
may result. 
b. If adjustment of the head harness fails to stop the leak, it is possi- 
ble that a hole or rip in the hose, outlet valve, or facepiece may have 
developed, and a minute visual inspection of the gas mask is necessary. 
2. Outlet valves occasionally stick and cause exhaled air to pass out 
between the facepiece and the face, especially during very cold weather 
or after the mask has been disinfected. In case of a sticking outlet 
valve, remove the facepiece and open the valve ports with a match 
stick, but be careful that the valve is not injured or torn in so doing. 
Talcum powder sprinkled on the inner surfaces of the outlet valve will 
prevent further sticking. Readjust the facepiece. 
■ 91.7. Mask Inspection.—Checking the mask as described is 
not a conclusive test of its serviceability. During the execution 
of the command check, liASK, if the facepiece fails to cling to 
the face and a leak is indicated, a minute visual inspection must 
he made. Visual inspections must also be made upon receipt of 
the masks and periodically thereafter for cleanliness and con- 
dition of the several parts of the gas mask. This inspection is 
made by the individual wearer. It is not executed as a pre- 
cision drill, but will be taught in the following manner: 
a. To inspect mask.—The command is: 1. Inspect, 2. MASK. 
Remove facepiece from carrier or face and hang it over left 
shoulder. Remove the canister from the carrier. Examine 
canister straps and check antidim. Examine canister. (See 
note 1.) Examine hose. (See note 2.) Replace canister in 
carrier. Minutely and carefully examine the eyepieces, outlet 
valve, facepiece, and head harness. (See notes 3, 4, 5, and 6.) 
16 DEFENSE AGAINST CHEMICAL ATTACK 
Persons with defective or faulty masks will report to the instruc- 
tor. All others will replace facepieces. 
Notes.—1. Serious defects in the canister are indicated by holes 
through the canister body, excessive rust and corrosion, and by loose 
or rattling contents. (Normally, the canister does not make any 
sound when shaken.) Rust or corrosion may be caused by water in the 
interior of the canister, resulting in caked and damaged contents. This 
will lower the chemical efficiency and cause marked increase in breath- 
ing resistance. Such a canister will be exchanged. Minor defects 
in the canister are faulty inlet valves and loose connections to the 
hose. These can be repaired in the organization. 
2. Hose may develop holes, splits, and tears due to accident. These 
may be temporarily patched in the field in an emergency, but should 
be replaced as soon as possible. Improper storage and incorrect place- 
ment of the hose in the carrier often cause kinks, undue stretching or 
tackiness, and permanent set of the rubber. Such hose should be 
replaced. 
3. If incorrectly stored, rubber of outlet valves may become sticky or 
tacky and later hard and cracked with a permanent set. Defective 
valves will be replaced. Occasionally, after disinfection, and also dur- 
ing freezing weather, the edges of the valve disk will freeze or stick, 
causing very high resistance to exhalation. When this happens, it 
is necessary to examine the valve and carefully open the ports. 
4. Facepieces are affected by improper storage and careless use. The 
rubber may, unless correctly placed in the carrier, take a permanent 
set and form leakage channels around the edges. Head harness attach- 
ments may become torn or loosened. Cracks and splits sometimes 
develop near the eyepieces. Eyelenses sometimes are badly scratched. 
Unless the damage is too great, facepieces usually can be repaired 
within the organization. 
5. If head harness is adjusted too tight or "with too great tension 
during drills and wearing exercises, the rubber threads of the elastic 
straps may break. Improper storage may cause the rubber threads 
to deteriorate and lose elasticity. A defective head harness should be 
replaced. 
6. Inspection of the carrier is habitually performed whenever the 
mask is to be laid away. The carrier should be inspected for tears 
or rips in the fabric, for broken or missing metal parts, and to insure 
that protective covers, protective ointment, and antidim are present. 
The carrier may also be inspected at such other occasions as are deemed 
necessary. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
552593°—43 3 
17 BASIC FIELD MANUAL 
Figure 49.1®.—Sling mask starting position. 
551593°—43 4 
18 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.1®.—Sling mask, completion of first count. 
19 BASIC FIELD MANUAL 
Fxguiib 49.10.—Gas alert position, shortening shoulder strap. 
20 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.1©.—Side carry position. 
21 BASIC FIELD MANUAL 
Figure 49.10.—Gas alert position driver of motor vehicle. 
22 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.1®.—Back carry position, sliding carrier to back. 
23 BASIC FIELD MANUAL 
Figuke 49.1®.—Back carry position, fastening body strap. 
24 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.10.—Side carry position, modified, carrier in lap. 
25 BASIC FIELD MANUAL 
Figure 49.1®.—Back carry position, with pack and carbine. 
551593°—43 5 
26 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.1®.—Back carry position, without pack, rear view. 
27 BASIC FIELD MANUAL 
Figukb 49.2©.—Removal of helmet. 
28 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.20.—Opening flap of carrier. 
29 BASIC FIELD MANUAL 
Figure 49.2®.—Removing facepiece from carrier. 
30 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.20.—Fingers straight and together. 
31 BASIC FIELD MANUAL 
Figukb 49.2®.—Thumbs inside the facepiece. 
32 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.2®.—Sweep head harness over the head. 
33 BASIC FIELD MANUAL 
Figure 49.2®.—Clear the facepiece. 
34 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.2®.—Check the mask 
35 BASIC FIELD MANUAL 
Figure 49.2®.—Fasten carrier. 
36 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.2®.—Mask adjusted, carrier at gas alert, driver of vehicle. 
37 BASIC FIELD MANUAL 
Figure 49.2®.—Mask adjusted, carrier at gas alert, mounted. 
38 DEFENSE AGAINST CHEMICAL ATTACK 
Figdhb 49.2@.—Shortening shoulder strap. 
39 BASIC FIELD MANUAL 
Figure 49.2@.—Mask adjusted, carrier at back carry with pack. 
40 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.3.—Testing for gas before removing masR. 
41 BASIC FIELD MANUAL 
Figure 49.4®.—Lift headpiece and remove facepiece. 
42 DEFENSE AGAINST CHEMICAL ATTACK 
Figuee 49.4®.—Replacing helmet, facepiece in crook of left elbow. 
43 BASIC FIELD MANUAL 
Figure 49.4®.—Placing head harness in facepiece. 
44 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 49.4©.—Opening carrier. 
45 BASIC FIELD MANUAL 
Figukb 49.4©.—Looping hose around canister. 
46 DEFENSE AGAINST CHEMICAL ATTACK 
Figukh 49.4®.—Starting Uose loop into carrier. 
47 BASIC FIELD MANUAL 
Fxudrb 49.4®.—Fastening the carrier. 
48 DEFENSE AGAINST CHEMICAL ATTACK 
■ 108.1. (Added.) Cleaning Outlet Valves.—a. General.— 
Outlet valves of masks will leak when coated or clogged with 
dust, sand, or other foreign matter. Gas enters the facepiece. 
Outlet valves will, therefore, be kept clean and free of foreign 
matter. 
b. Cleaning.—(1) Outlet valves can usually be cleaned by 
wiping them with a dry cloth, or a cloth moistened with warm 
water may be used if necessary. 
(2) In the disk type outlet valves both the rubber disk and 
the valve seat will be cleaned. If the valve has a valve guard, 
the guard may be removed by unscrewing it to facilitate clean- 
ing. If the valve guard should be cemented in place, procedures 
to be followed are those recommended in paragraph 42%, 
TM 3-205. 
(3) Outlet valves other than disk type will be cleaned by 
wiping the outside of the rubber valve and carefully cleaning 
the ports with a cloth wrapped around a small wooden stick. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
■ 114. Use. 
a. Impermeable clothing.—Impermeable suits are made of 
coated materials which will not allow liquid vesicants or vapors 
to pass readily through them. They afford complete protec- 
tion from vapors or any size drops of liquid vesicants for 
varying periods of time. It should be borne in mind, how- 
ever, that the nitrogen mustards, in liquid form, penetrate 
rubber gloves and rubberized fabrics with greater rapidity 
than does ordinary mustard gas. Since there is * * * are 
likewise worn. 
b. Permeable clothing.—The permeable type of clothing con- 
sists of garments treated in such a manner that they will pro- 
tect the wearer from field concentrations of vapor and small 
drops of vesicant chemical agents. Large drops will exhaust 
the chemical in the clothing at the point where the liquid 
wets the fabric, and some of the agent will then penetrate 
to the body of the wearer. Protective clothing reacts in the 
same way to drops of ordinary mustard gas, nitrogen mus- 
tard, and to lewisite. It is to be noted, however, that lewisite 
is approximately 45 percent heavier than ordinary mustard BASIC FIELD MANUAL 
gas; consequently, the drops of lewisite against which the 
clothing gives complete protection are somewhat smaller 
than those of ordinary mustard gas. The ordinary field 
* * * also be worn. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) DEFENSE AGAINST CHEMICAL ATTACK 
Section IX (Added) 
EYESHIELD 
■ 125.1. Purpose.—Eyeshield Ml is designed for the protection 
and use of troops in the theater of operations against chemical 
spray attack by enemy aircraft. Its use may be extended to 
protection of the eyes against dust, wind, or blown sand. 
a. Description.—The eyeshield (fig. 100.1 is a one-piece, flexi- 
Figure 100.1.—Eyeshield, Ml, with nomenclature. 
ble, transparent, plastic goggle cut to fit closely over the bridge 
of the nose and around the eyes. It is held in place over the 
eyes by a headstrap which the wearer may adjust so that the 
eyeshield will fit comfortably (fig. 100.2). One section of the 
headstrap is of elastic tape while the remainder is of cotton 
webbing. Eyeshields are issued in a waterproofed, open-end 
envelope to each soldier in the theater of operations, and will be 
51 BASIC FIELD MANUAL 
Figure 100.2.—Eyeshield adjusted. 
52 DEFENSE AGAINST CHEMICAL ATTACK 
carried in the gas mask carrier. Eyeshields are expendable 
and will be discarded when contaminated. 
I). Use.—The eyeshield is worn whenever enemy airplanes are 
known to be in the vicinity or at any other time when protection 
for the eyes is needed. When personnel are contaminated by 
liquid agents, they must first decontaminate and apply protec- 
tive ointment before changing eyeshields. As soon as a con- 
taminated eyeshield is removed and discarded another should 
be adjusted in preparation for any recurrence of the attack. 
The eyeshield is not designed to fit beneath the gas mask and 
should be removed prior to adjusting the mask. The face must 
be decontaminated before the mask is adjusted. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
■ 126. Personal Protective Measures.—a. Protective ointments 
(Superseded).—Protective ointments will be used as a first-aid 
measure only AFTER contamination by vesicant liquids, and not 
as a preventive. Instructions printed in training literature and 
on tubes of protective ointment which state that these ointments 
may be used as a “preventive” or “protection” against vesicants, 
or which state that the ointment is to be “mixed well with 
vesicant on skin,” are rescinded. 
(1) Description.—Protective ointments Ml, M2, M3, and M4 
are Issued in collapsible tubes which in turn are packed in indi- 
vidual cardboard containers. A quantity of absorbent tissue 
accompanies ointment M4. 
(2) Instructional use.—Instructional use of protective oint- 
ments in training will be limited to three successive applications 
of the ointment, as repeated use will cause serious irritation. 
The ointment should not be applied to the tender areas of the 
body, such as the scrotal regions, during training or for test 
purposes. 
(3) Use.—Ointments are to be used similarly and MUST be 
applied immediately, or within a very few minutes, following 
liquid contamination of the skin in order that the greatest benefit 
may be obtained. If reddening of the skin has already occurred, 
ointment will not be applied. Protective ointments may be used 
on any areas of the body EXCEPT the eyes, with care being 
53 BASIC FIELD MANUAL 
exercise'd to keep ointment out of the eyes. Three steps of 
decontamination are desirable; 
(a) First.—Dry absorbent tissue is carefully applied in a 
blotting or dabbing manner to remove agent from the skin. 
Extreme care must be exercised by the individual not to spread 
the agent to uncontaminated areas. 
(fo) Second.—A quantity of protective ointment, sufficient for 
the area contaminated, is squeezed on the contaminated skin 
area, rubbed with the fingers for approximately 15 seconds, and 
then wiped off. This is done three times without interruption. 
(c) Third.—When practicable the area is finally washed with 
soap and water. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
54 DEFENSE AGAINST CHEMICAL ATTACK 
■ 127. Detection DEViCES.—Since mustard gas, nitrogen mus- 
tards, and lewisite may be made practically odorless, detection 
devices are necessary for warning against these agents. For 
this purpose, * * * are described below. 
a. Paint, liquid vesicant detector M5.—This paint is to be 
applied by brush or spray to surfaces suitable for painting, 
such as fences, lamp posts, helmets, hoods and fenders of 
vehicles, or other material readily visible in areas where vesi- 
cants might be used, in order to render them sensitive to liquid 
vesicant spray. It should constitute part of the camouflage 
pattern on helmets and on hoods and fenders of vehicles. 
Although the paint is touch dry within 2 hours, a consid- 
erably longer tjme is required for complete dryness. For 
this reason all painting should he carried out in the very late 
afternoon, dusk, or early evening to permit overnight dry- 
ing. The wet paint loses much of its sensitivity to vesicant 
agents if exposed to the heat of the sun. The length of life 
of the paint under continuous exposure to severe conditions 
of heat and sun can safely be regarded as 1 week. Under 
milder conditions the life is much longer, extending, under 
temperate conditions, to months. The color of the paint is 
yellow after its usefulness has been destroyed by light. It 
should be understood that conditions which cause the de- 
terioration of ordinary paint will also affect the detector 
paint. Ordinary paint has a longer life than detector paint. 
In the desert or jungle it is difficult to predict exact durabil- 
ity of detector paint due to lack of knowledge of the amount 
of abrasion by sand or thick vegetation. Rough handling of 
detector-painted surfaces will likewise decrease the life of 
the detector paint. It should therefore be remembefed that 
under severe conditions helmets and vehicle surfaces should 
be repainted each week. Conditions of extreme heat, above 
150° Fahrenheit, will cause the paint to turn reddish-brown. 
This does not destroy the value of the paint, for the color 
produced by vesicants is still easily visible on this reddish- 
brown color, but the surface may have to be repainted for 
camouflage purposes. The paint is * * * wherever they 
strike. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
55 BASIC FIELD MANUAL 
■ 130. Water Treatment. 
b. Water that is * * * water supply battalion. 
Note (Added).—Since the senses are unreliable to detect nitrogen 
mustards, and since the usual methods of detection of these agents are 
not applicable to contaminated water, when areas immediately adjacent 
to small bodies of water are found to be contaminated by the nitrogen 
mustards, the water must also be considered contaminated. However, 
dangerous contamination of a large body of water or of a rapidly flowing 
stream is unlikely. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
■ 132. For Mustard Gas. 
b. Chlorinated lime (bleaching powder). 
(3) (Added.) A “brush-and-bucket” method consists of mixing 
the 50-50 slurry in a 14-quart galvanized iron bucket. If mixed 
by volume rather than by weight, 5 shovelfuls of chlorinated 
lime are used with 3 gallons of water. A mixture of thick, pasty 
consistency is suitable for walls but should be diluted for hori- 
zontal surfaces. The slurry is applied to surfaces with brushes 
or swabs. Complete coverage is necessary, followed by scrub- 
bing to dislodge vesicant and fill cracks with slurry. If prac- 
ticable, the slurry should remain in contact with the contami- 
nated surface for 6 to 24 hours, after which it should lie removed 
by washing down, scrubbing, and rinsing with water. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43. 
■ 133. For Lewisite and Other Aesenicals.—Decontamination 
for lewisite * * * in the area. After treatment with water, 
a lewisite area should, if practicable, be covered with a layer of 
earth, sand, or ashes, and materiel treated with a caustic solu- 
tion, such as washing soda or lye. 
■ 137. Decontaminating Apparatus, 3-Gallon.—The 3-gallon 
pressure * * * noncorrosive decontaminating agent. The 
apparatus is * * * the required pressure. It is best used 
when decontaminating materiel rather than contaminated ter- 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
56 DEFENSE AGAINST CHEMICAL ATTACK 
rain. Bleach slurry, formerly applied with this apparatus 
will no longer be used in this equipment but will be applied 
by the “brush-and-bucket” method. In no instance will 
noncorrosive decontaminating agent be stored in the appa- 
ratus. Instead, any unused solution will be dumped, the 
apparatus drained, and then rinsed thoroughly twice with 
acetylene tetrachloride. The acetylene tetrachloride will then 
be permitted to evaporate completely before the apparatus is 
reassembled. 
[A. G. 300.7 (2 Jul 43).] (C 1, 11 Sep 43.) 
By order of the Secretary of War: 
G. O. MARSHALL, 
Chief of Staff. 
Official : 
J. A. ULIO, 
Major General, 
The Adjutant General. 
57 
U. S. GOVERNMENT PRINTING OFFICE: 1943 FM 21-40 
*C 2 
BASIC FIELD MANUAL 
DEFENSE AGAINST CHEMICAL ATTACK 
Changes 
No. 2 
WAR DEPARTMENT, 
Washington 25, D. C., 20 December 1943. 
FM 21-40, 7 September 1942, is changed as follows: 
■ 36. Alarms. 
b. Local.—Local alarms are * * * gas is recognized. 
Except in the case of airplane spray attack, c below, they are 
usually given only with alarm devices which produce a sound 
not easily confused with other sounds encountered in combat. 
Alarm devices of this type may include the gas alarm Ml 
(fig. 14.1), or the British gas rattle. Bells, metal triangles, 
steel rails, pipes, or empty 75-mm or 105-mm shell cases, 
when struck rapidly and continuously with an iron or steel 
striking rod, may be used as improvised alarms. All personnel 
should * * * its distinctive sound. 
c. (Added.) Warning of airplane spray attack.— (1) In the 
event of airplane spray attack, warning will be given immediately 
by the cry of “SPRAY.” 
(2) This warning cry of “Spray” will be given only when 
attacking aircraft are actually observed to begin a spray attack. 
(3) When the cry of “Spray” has been given, other types of 
gas alarm will not be sounded unless a heavy concentration of 
vapor occurs. 
[A. G. 300.7 (14 Sep 43).] (C 2, 20 Dec 43.) 
■ 44. Division Chemical Officer. 
g. (Superseded.) When conditions warrant, a situation map 
will be prepared and maintained by the division chemical officer. 
Tins map will embrace the area over which the division is 
operating, together with so much of the adjoining area as may 
be necessary for a proper understanding of the situation. The 
scale of the map should be the same as that of the map used 
by the division G-2 or G-3 in preparing G-2 or G-3 overlays. 
The situation map should show at all times the areas where 
chemical agents have been laid down by the enemy and also 
*The individual items in this change will be cut apart and pasted over 
the specific paragraphs or subparagraphs affected. 
563064°—43 EM 21-40 
C 2 
BASIC FIELD MANUAL 
Figure 14.1.—Gas alarm Ml. 
by friendly troops. Provision must be made to indicate the 
type of gas used, the relative degree of contamination (in the 
case of persistent gases), and the date the gas was laid down 
or the contaminated area discovered. Division boundaries, 
certain important installations, and items of like nature should 
be shown as well as other data which may be pertinent to the 
particular situation. However, items which may change fre- 
quently, such as troop dispositions, which are usually shown 
on G-2 or G-3 overlays, should not be shown on the gas situa- 
tion map. In those cases where it is desirable to include fre- 
quently changing data on the map a sheet of acetate film may 
be fixed in place over the map and data inscribed on this sheet 
[A. G. 300.7 (14 Sep 43).] (C 2, 20 Dec 43.) 
1 DEFENSE AGAINST CHEMICAL ATTACK 
I’M 21-40 
C 2 
with wax pencils. These inscriptions can easily be removed 
at any time by rubbing with a cloth. All possible sources of 
information will be used in order that the data included on this 
map will be complete, accurate, and up to date. One of the 
enlisted men of the division chemical section should be specially 
trained for the purpose of preparing and maintaining the gas 
situation map and doing other work of a similar nature. 
(See FM 3-5.) 
■ 52.1 (Added) Field Duties.—a. In the field, whenever there 
is danger of gas being used, each gas noncommissioned officer 
should have with him at all times a supply of liquid vesicant 
detector paper or vesicant detector crayons. Whenever making 
a reconnaissance, a gas noncommissioned officer should be sup- 
plied with containers for collecting samples of contaminated 
earth or other material. He should also be provided with equip- 
ment for marking contaminated areas (placards, signs, or similar 
improvised markers). 
b. On the march, a gas noncommissioned officer, provided with 
a chemical agent detector kit, should always accompany the 
point of the column. When deployment appears imminent, gas 
noncommissioned officers with chemical agent detector kits, if 
available, should accompany flank patrols. When deployed, one 
of the company gas noncommissioned officers should remain 
habitually in the neighborhood of the company commander in 
order to be immediately available in any situation where gas is 
used. Similarly, the battalion and regimental gas noncom- 
missioned officers should remain in the vicinity of the gas officers 
whose assistants they are. Wherever possible, these gas non- 
commissioned officers should carry chemical agent detector kits. 
c. In addition to other duties, all gas noncommissioned officers 
will assist when necessary in first aid procedures for gas 
casualties. 
[A. G. 300.7 (14 Sep 43).] (C 2, 20 Dec 43.) 
■ 119.1 (Added) Test for Protective Value.—The kit, testing, 
impregnite in clothing, Ml provides a method for determining 
when impregnated clothing no longer affords adequate protec- 
tion against blister-gas vapors or droplets. The test can be 
used in the field, as well as for clothing in storage or at laundry 
installations. 
[A. G. 300.7 (14 Sep 43).] (C 2, 20 Dec 43.) 
2 FM 21-40 
C 2 
BASIC FIELD MANUAL 
a. Description.—The complete test kit (fig. 99.1) consists of 
an olive drab cotton-duck kit, 614 inches wide, 4% inches high, 
and approximately 1 inch thick. It weighs about 1 pound. 
Two loops for attachment to waist belt are provided. 
b. Contents.—The contents of the kit include the following: 
(1) Solvent, in 1-ounce bottle. (Bottle A.) 
(2) One heavy-glass eye dropper for solvent. 
(3) One-ounce bottle (Bottle B) with eye dropper. This 
bottle contains two white tablets. These tablets are dissolved in 
water (c below) to prepare the test solution. 
(4) Book of test papers. 
(5) One-ounce bottle (Bottle C) with eye dropper. This 
bottle contains two light-orange-colored tablets. The tablets 
are dissolved in water (c below) to prepare the neutralizing 
solution. 
(6) Soft, black pencil for marking spots on garments. 
(7) Instruction card with complete directions for test. 
c. Preparing solutions.—When the kit is to be issued from 
the depot the bottles containing the tablets (Bottle B and Bot- 
tle C) will be filled with clean rain or well water, or preferably 
with distilled water, to within about % inch of the lower part 
of the neck of the bottle, and the bottles rotated or shaken until 
the tablets dissolve. Caution: Chlorinated water must not be 
used. The neutralizing solution tablets are colored with a dye to 
distinguish them from the test solution tablets. This dye colors 
the neutralizing solution greenish yellow. 
d. Test procedure.— (1) Place one drop of solvent (Bottle A) 
on the cloth to be tested. 
(2) Place one drop (no more) of test solution (Bottle B) on 
the spot wetted by the solvent. 
(3) After 2 or 3 seconds (not over 10 seconds), blot the liquid 
from the cloth with a piece of test paper. Use firm pressure 
while blotting and make certain that the liquid from the cloth 
is taken up by the paper. 
(4) Remove the paper from the cloth and compare the extent 
of the color patch developed on the paper with that shown in 
figure 99.2. 
(a) Positive results, indicating that the cloth has good pro- 
tective value, are characterized by a blue-black color developed 
throughout all or the greater portion of the spot on the paper 
(A and B, fig. 99.2). . 
4 EM 21-40 
C 2 
DEFENSE AGAINST CHEMICAL ATTACK 
Figdee 99.1.—Kit, testing, impregnite in clothing, Ml. 
[A. G. 300.7 (14 Sep 43).] (C 2, 20 Dec 43.) FM 21-40 
C 2 
BASIC FIELD MANUAL 
Positive results 
Safe garments 
Negative results 
Reimpregnation indicated 
[A. G. 800.7 (14 Sep 43).] (C 2, 20 Dec 43.) 
Figure 99.2.—Test results. 
(ft) Negative results, indicating that the garment is low in 
protective power, may show a ring of color formed around the 
edge of the spot, with scattered color within the ring (C and D, 
fig. 99.2), or, where the impregnite content is unusually low, may 
show no color at all. If there is doubt about a result, the test 
should be repeated. 
(5) After the test has been completed, place a drop of the 
neutralizing solution (Bottle C) on the tested spot of the gar- 
ment and allow it to soak into the cloth. The spot is then marked 
with the black pencil to avoid retesting the same area. 
e. Portions to be tested.—Sections of clothing subjected to the 
effects of friction and perspiration should be used as key points 
for testing because the impregnite content deteriorates more 
rapidly in such parts. 
/. Selection of test garments.—Clothing for test should be 
representative of a lot which has been stored or worn under 
approximately the same conditions. The results can then be 
taken as indicating the condition of the entire lot. 
g. Number to be tested.—Following is the proportion of gar- 
ments to be tested under certain conditions: 
(1) From storage: at least y2 of 1 percent (1 percent of 
clothing taken from storage for issue). 
(2) After 2 weeks’ wear, if not laundered, and not to be 
laundered before additional wear: at least 5 percent. 
(3) After each laundering: at least 5 percent. 
(4) After exposure to blister-gas vapor: at least 10 percent. 
h. Disposition of clothing.— (1) When one-half or more of the 
tested garments show negative results, reimpregnation of the 
entire lot is necessary. 
6 FM 21-40 
C 2 
DEFENSE AGAINST CHEMICAL ATTACK 
(2) When more than one-half of the test garments show 
positive results, and the remainder show the presence of some 
impreg iite (C, fig. 99.2), reimpregnation is not necessary. 
(3) When more than one-half of the test garments show 
positive results, and 'a high percentage of the remainder show 
the presence of very little or no impregnite (D, fig. 99.2), the 
lot should be reimpregnated, or each garment tested and the 
lot sorted. 
■ 133.1 (Added) Use of Protective Ointment.—Protective 
ointment Ml, M2, M3, or M4 may be used for the emergency 
decontamination of individual weapons and certain items of 
individual equipment as follows: 
a. Weapons—(1) Wipe dry of all liquid contaminants (H, 
L, etc.) and bury or burn wiping material. 
(2) Spread ointment well over all contaminated metal, wood, 
and leather surfaces, rub vigorously, and allow to remain for 
15 minutes. 
(3) Wipe all surfaces dry of ointment. 
(4) As soon as tactically permissible, disassemble the weapon, 
clean thoroughly, oil all metal parts, and reassemble. 
b. Entrenching tools.— (1) Scrape off any contaminated earth 
or other material that may be upon the tools. 
(2) Apply ointment to all contaminated surfaces except the 
blade, and allow to remain for 15 minutes. 
(3) Wipe all surfaces dry of ointment. 
(4) Remove liquid contamination from the blade by plunging 
the blade several times into earth or sand until clean. 
c. Oas mask.— (1) Facepiece.—Both exterior and interior 
of the facepiece and valves will be wiped dry of liquid contam- 
ination, coated with ointment, and this wiped off after 15 
minutes. To be most effective, ointment must be applied within 
3 minutes after contamination. Ointment will not be used on 
the eyepieces because it will etch them severely. (Eyepieces 
will be decontaminated, so far as possible, by rubbing, first with 
a dry cloth or absorbent paper, next with a damp cloth, drying 
and applying antidim.) Care should be taken to insure that 
the inf erior of the facepiece is wiped dry of ointment, and that 
no ointment is permitted to remain within the valves, or clogging 
[A. G. 300.7 (14 Sep 43).] (C 2, 20 Dec 43.) 
7 FM 21-40 
C 2 
BASIC FIELD MANUAL 
will result. Any odor of ointment detected during subsequent 
wearing of the mask may be disregarded. A contaminated gas 
mask will be treated daily with ointment, as outlined above, 
until it can be completely decontaminated by other means. 
(2) Hose.—Ointment will be used to decontaminate the hose. 
To be wholly effective, ointment must be applied immediately 
after contamination. This will likewise prevent contamination 
by the hose of the inside of the facepiece. It should be 
thoroughly understood, however, that only one surface of the 
hose (the outside) can be treated with protective ointment. 
It is therefore impracticable to use ointment to decontaminate 
a heavily contaminated hose. Vesicant liquid will be quickly 
absorbed by the hose and produce vapor within. 
(3) Carrier, gas mask.—As too large a quantity will be re- 
quired for effective decontamination, ointment will not be used 
to decontaminate the gas mask carrier. Instead, the carrier 
will be decontaminated by aeration or scrubbing with soap and 
water. 
d. Leather.—The leather chin strap of the helmet and the 
leather holster may be decontaminated by ointment in the same 
manner as other items. 
e. Clothing.—Protective ointment will be used to decontami- 
nate clothing which is lightly contaminated with not more than 
20 to 30 drops of mustard gas or other blister gas. The oint- 
ment will be applied to both sides of the cloth and rubbed in 
thoroughly on and around each spot, after which the soldier will 
put his clothes on again and proceed with his duties. If 
clothing is heavily contaminated, it should be removed and re- 
placed. It must be remembered that the use of protective oint- 
ment to decontaminate clothing is only a temporary measure. 
As soon as the tactical situation permits, the clothing will be 
changed. 
[A. G. 300.7 (14 Sep 43),] (C 2, 20 Dec 43.) 
By order of the Secretary of War : 
Official : 
J. A. ULIO, 
Major General, 
The Adjutant General. 
G. C. MARSHALL, 
Chief of Staff. 
8 
u. S, GOVERNMENT PRINTING OFFICE: 1943 FM 21-40 
*C 3 
BASIC FIELD MANUAL 
DEFENSE AGAINST CHEMICAL ATTACK 
Changes 
No. 3 
WAR DEPARTMENT, 
Washington 25, D. C., 28 April 1944. 
FM 21-40, 7 September 1942, is changed as follows: 
■ 7. Chemical Agents. 
e. Irritant smokes. 
(2) Diphenylchlorarsine (DA).—Diphenylchlorarsine is a 
* * than with DM. Caution: When irritant smokes 
(vomiting gases) are released in inclosed spaces concentra- 
tions may be so high as to cause serious symptoms and some- 
times death. 
f. Screening smokes. 
(3) White phosphorus (WP).—White phosphorus is * * * 
effect upon personnel. 
Note (Added).—Precautions.—Screening smokes consist of finely 
divided solid particles or liquid droplets suspended in the atmosphere. 
The suspended material may consist of metallic salts, metallic oxides, 
inorganic acids, hydrocarbons, and other materials. Any of these sub- 
stances may be injurious if heavy concentrations are breathed for rela- 
tively long periods of time. Although the gas mask is not required for 
protection against ordinary smoke clouds, it should be worn in dense 
smoke to prevent inhaling large amounts of substances which may have 
irritating or injurious effects on the body. Therefore, if personnel must 
remain close downwind from smoke generators, gas masks should be 
worn to assure adequate protection. Since some individuals are more 
sensitive than others to these agents, gas masks should be worn if 
unpleasant effects are noticed. If screening smokes are released in 
inclosed spaces, heavy concentrations may result. Unmasked personnel 
must not enter such inclosures. When the enemy employs smoke, the 
gas mask must be worn to guard against possibility that toxic chemical 
agents may be dispersed along with the smoke. The mask may be 
removed when it is determined that the smoke does not conceal a toxic 
agent. 
*These changes supersede section II, Training Circular No. 57, War 
Department, 1942. 
582350°- -44 BASIC FIELD MANUAL 
(4) Precautions (Added by C 1).—Rescinded. 
g. Incendiary agents.—The purpose of * * * phosphorus, 
and oil. Appendix VI contains further information on in- 
cendiaries, together with methods of combatting them. 
(1) Thermit.— (a) General.-—Thermit is an * * * mod- 
ification of thermit. It is a mixture of iron oxide, aluminum, 
barium nitrate, and small amounts of sulfur and castor oil. 
(ft) Counteractive measures.—Resci nded. 
(2) Magnesium.— {a) General.—The German “Elektron” 
* * * of about 2,800° F. American magnesium bombs are 
described fully in TM 9—1980. 
(ft) Counteractive measures.-—Rescinded. 
(3) White phosphorus. 
(&) Counteractive measures.—Rescinded. 
(4) Oil 
(5) Counteractive measures.—Rescinded. 
■ 9. General First-Aid Measures (As changed by C 1). 
i. First aid for visicant casualties. 
(2)Breathing passages and digestive system (Superseded).— 
First aid cannot cope with the effect of visicauts (blister gases) 
on the breathing passages and digestive system. Speed is es- 
sential in removing vesicant liquid (especially mustard gas) 
from areas about the face to prevent inhaling vapors arising 
from the liquid. Care must also be exercised against vapors 
from contaminated clothing or personal equipment. The vic- 
tim should be handled similarly to a lung irritant (choking gas) 
casualty. If medical aid is not available and evacuation is not 
possible for 24 hours or longer, “wound tablets” from the first 
aid pouch should be taken according to directions, to prevent 
pneumonia. 
■ 110. Rules for Care and Use. 
2 DEFENSE AGAINST CHEMICAL ATTACK 
c. Rules for the individual. 
(6) (Added.) Do not remove the mask in a gas concentra- 
tion because a slight odor of gas is detected in the facepiece. 
If the facepiece is properly fitted and the mask in good condi- 
tion, slight odors of gas in the facepiece should cause no alarm. 
In case the odor persists or becomes stronger, report to your gas 
noncommissioned officer as soon as the tactical situation permits. 
3 BASIC FIELD MANUAL 
Appendix VI (Added) 
COMBATTING INCENDIARIES 
Section I 
GENERAL 
■ 1. Characteristics and Control of Common Inoenmary 
ACxEnts.—The common incendiaries are phosphorus, oil, thermit, 
and magnesium. Combinations of these are also used (par. 7g). 
Each type is easily recognized. All are ordinarily controlled 
by use of water. 
a. Phosphorus.—White phosphorus burns with a bright yellow 
flame, giving oft white smoke. Phosphorus is easily controlled 
by flooding with water, but as soon as the water evaporates, it 
reignites. As phosphorus on the skin causes a severe burn, 
fragments should not be touched with bare hands. 
b. Oil.—Oils, kerosene, benzine, and rubber burn with a yel- 
lowish flame and give off dense, black smoke. The oil fire 
should be attacked with suitable fire extinguishers (par. 7c, 
app. VI) or smothered with a blanket, dirt, or sand. Water is 
used to fight fires started by oil fires, but should not be used 
directly on oil. 
c. Thermit.—Thermit burns with an orange glow and gives 
off intense heat. It is an igniter used in magnesium bombs. 
It is. also used in large thermit incendiaries which are virtually 
uncontrollable, being violent but of short duration. Efforts 
should be directed toward control of the resulting fires. 
d. Magnesium.—(1) Characteristics.—Magnesium burns with 
an intense, white glow and emits a white smoke. Water on 
magnesium makes it burn faster, but a small magnesium bomb 
can be extinguished by dropping it into a pail of water. 
(2) Methods of control.— (a) A jet of water shot directly 
upon a magnesium bomb causes scattering and rapid burning. 
This is a quick method used where scattering of the metal is 
of no importance. The fragments can be quickly extinguished 
with the jet. 
(6) Where much readily flammable material is nearby, use 
a coarse spray. 
4 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 132.—Types of incendiaries. 
5 BASIC FIELD MANUAL 
■ 2. Methods of Incendiary Attack.—Incendiaries usually 
are— 
a. Dropped in bombs from airplanes. (See FM 9-40 and TM 
9-1980.) 
ft. Hurled by weapons and hand. 
G. Installed manually. 
■ 3. Strategy and Tactics.—Incendiary bombs may cause 
more destruction than any other aerial munition. Incendiaries 
may cause huge fires and heavy loss of life and property. The 
incendiary bomb is considered a strategic rather than a tactical 
weapon, and it has been used mainly against rear-area installa- 
tions, yet its tactical targets include ammunition dumps, ad- 
vance depots, railheads, airdromes, and supply columns. 
Incendiary shell, grenades, and flame throwers are primarily 
tactical. 
a. Types of attaclc.—(1) Large incendiary bombs normally 
are used only on important installations (point targets), such as 
airdromes, railheads, docks, depots, and factories. 
(2) Small incendiary bombs are customarily dropped in 
clusters against area targets. These bombs disperse in falling, 
the object being to start a number of separate fires which merge 
into a major conflagration. Bombing is coordinated in order 
to lay bombs in the most effective pattern. 
ft. Secondary missions.— (1) Explosive incendiary bombs often 
are included in incendiary bomb clusters. Besides starting 
fires, they impede incendiary defense. 
(2) Fires started may light the way for high-explosive, pre- 
cision bombing. 
■ 4, Factors Favoring Incendiaries.—a. Targets. 
(1) Combustible roofs and wooden buildings. 
(2) Combustible supplies in storage. 
(3) Areas congested with buildings. 
(4) Dry grass, ripe grain, and woods. 
6, Conditions.—(1) Dry weather. 
(2) High wind. 
(3) Poorly trained and equipped defense organizations 
(4) Inadequate water supply. 
■ 5. Means of Defense.—Defense against incendiaries, while 
fundamentally passive, must be aggressively conducted. 
6 DEFENSE AGAINST CHEMICAL ATTACK 
а. Precautionary measures.—Inspections should be made to in- 
sure that— 
(1) Flammable materials are kept in nonflammable con- 
tainers. 
(2) Waste materials are not allowed to accumulate. 
(3) Wooden surfaces, where practicable, are coated with 
whitewash, water glass solution, or other fire-resistant mate- 
rial (properly camouflaged). 
(4) Materials for fighting incendiaries are readily accessible. 
(5) A practical incendiary spotting and alarm system is in 
operation. 
(6) Combustible supplies are dispersed. 
(7) Ingenuity is employed in improvising supplementary 
equipment. 
б. Incendiary defense organization.— (1) To combat incendi- 
aries successfully, a unit defense organization should be estab- 
lished and taught to use available equipment. 
(2) Periodic defense drills should be held. Anti-incendiary 
discipline of the entire unit should be stressed. 
(3) Handling of small incendiaries is a technique that the 
individual soldier can be taught, just as he is taught the tech- 
nique of individual gas protection. 
(4) A fire guard for first-line defense should be established, 
consisting of individual fire guards equipped with and trained 
to use simple fire-extiguishing equipment. 
(5) If civilian communities with organized fire-fighting serv- 
ices are near, liaison should be maintained in order to obtain 
aid for control of fires. 
Section II 
PROTECTIVE MEASURES 
■ 6. General.—Plans for defense against incendiary attack 
cannot be as detailed when operating in the field as when in 
garrison. Much fire-fighting equipment ordinarily at hand in a 
permanent installation will not be available. Nevertheless, the 
same basic principles apply. 
■ 7. Equipment foe Defense.—a. General.—In the field, incen- 
diaries and the fires that they start must be controlled with 
7 BASIC FIELD MANUAL 
equipment on hand for fighting ordinary fires and with im- 
provised equipment. This includes water buckets and barrels, 
sand and sand mats, garden and fire hose, burlap bags, axes, 
shovels, flashlights, rope, goggles, and gloves. Pump tanks, 
3-gallon or 400-gallon decontaminating apparatus, and soda-acid 
or carbon dioxide extinguishers may also be available. Fire- 
fighting equipment must be kept in convenient, readily accessible 
places known to all. 
b. Hose.—Prompt flooding with a stream of water from a hose 
will soon extinguish or control most small incendiary bombs of 
any type. 
c. Fire extinguishers.—Most fire extinguishers can be used. 
Their chief disadvantage is small capacity. Use of the carbon 
tetrachloride extinguisher is not advisable in confined spaces be- 
cause of the possible generation of toxic fumes. Soda-acid and 
water types should not be used directly on oil. 
d. Water barrels and buckets.—Barrels (kept full of water) 
and buckets should always be available. In freezing weather, 
salt should be added to the water in outdoor barrels. 
e. Sand.—Even if there is no lack of other equipment, sand- 
bags should be conveniently placed, and containers of dry sand 
should be available for smothering effect. Twenty-pound sand- 
bags are best for quick and easy handling. Twenty-pound bags, 
15 by 12 by 3 Inches, are known as sand mats. 
. f. Other equipment — Pump tanks, knapsack type pumps, or 
the 3-gallon decontaminating apparatus are useful when fire or 
garden hose is not available. Shovels may be used to scoop up 
bombs or their molten particles for removal to places of safety. 
The 400-gallon decontaminating apparatus is excellent for fight- 
ing fires. 
■ 8. Organization for Defense.—a. Existing organisation.— 
The organization against air attack, existing at every military 
installation, must provide for incendiary defense. 
b. Fire department cooperation.—A single small incendiary 
may cause an appliance fire—one which cannot be brought under 
control by a fire-fighting squad, but must be attacked with pro- 
fessional fire-fighting apparatus. In a theater of operations, 
large appliance fires are handled by Army engineer fire-appli- 
ance troops. In the United States, civilian fire-fighting organi- 
zations or civilian employees of the Army must handle these 
larger fires. 
8 DEFENSE AGAINST CHEMICAL ATTACK 
PROTECTIVE EQUIPMENT 
Figure 133. (Added.) 
9 BASIC FIELD MANUAL 
Regular Organized 
Mobile Units 
{> Operations Staff; 
[POST SURGEON 
First Aid 
Decontamination 
of personnel 
General Staff (G-l. G-2. C-3. G-A) 
Essential air raid protection organization for military establishments. 
I File Clerk! 
Sub- 
SectorI 
Org 
Warden 
ESSENTIAL AIR RAID PROTECTION ORGANIZATION FOR MILITARY ESTABLISHMENTS 
Chief Air Raid Warden] 
Bks or Bldg Warden 
Post Warden 
Fire Guards 
Fire Guard Parties' 
Clerical Staff 
I Panel Clerk! 
Sector 
Sub- 
Sector 
I Plotting Clerj 
\ COMMANDING OFFICER 
-Executive Office^. 
Traffic Control 
Special Civilian Guards! 
Security 
Guards 
ARP OFFICER 
CWS 
MP 
Guards 
1— 
Sentries I 
Aux Guard 
Details 
T 
QM 
PROVOST MARSHAL | 
Hq Comdt 
Pers & Equip to Handle 
Incend Bomb Fires 
Standing Orders 
for Fire Defense 
Fire Guards 
Fire Guard Parties 
Morale 
Welfare 
Chaplain 
Fire Dept and/or 
Aux Fire Dnits 
Fire Rescue 
Special Staff 
Com 
Signal 
POST ENGINEER I 
IfIRE MARSHALI 
I Structures I 
■ Camouflage I 
Maintenance 
& Repairs 
JBIacH.9at.sj 
I Rescue 
I Demolitions I 
Bomb Ren 
Ordnance 
10 DEFENSE AGAINST CHEMICAL ATTACK 
c. General plum.—While no detailed plan will coyer all situ- 
ations. the following are important points in setting up a de- 
fense plan: 
(1) Assign fire guard duty in addition to regular duty. Sta- 
tion fire guards at point targets or important installations and 
use them as patrols in important areas. The number and lo- 
cation of fire guards will depend on study of the susceptibility 
of particular areas to incendiary attack. 
(2) Improvise additional equipment. 
(3) Keep an inventory of locations of all materials and equip- 
ment useful in fighting incendiary bombs. This record is main- 
tained at the control center where fire-fighting activities are 
coordinated. 
(4) Keep fire-fighting supplies and equipment near all vital 
centers. 
(5) A military area should be divided into sectors, with an 
officer responsible for the organization and its functioning in 
each sector. 
(6) An air raid protection organization should be set up. 
The accompanying chart, “Essential Air Raid Protection Or- 
ganization for Military Establishments,” will serve as a guide. 
d. Training.—All personnel should be trained to use available 
equipment and taught to recognize various types of incendiaries 
and their characteristics. 
e. Advance planning.—(1) General.—Advance planning, with 
complete understanding of the plan by all responsible officers, is 
essential. Surveys should be made and a standing operating 
procedure should be established. Simplicity of plan is of prime 
importance. 
(2) Classification of areas.—As part of the advance planning, 
areas should be classified according to— 
(а) Type of construction. 
(б) Amount of roof coverage, 
(c) Tactical importance. 
■ 9. Methods of Combatting Incendiaries in Important Struc- 
tures.—a. General.—When an incendiary falls into an impor- 
tant building or area, such as an oil or ammunition depot, an 
attempt must be made to control the fire in spite of the risk 
involved. This also is true in the case of any structure the 
burning of which might cause a critical fire. 
11 BASIC FIELD MANUAL 
6. Precautionary measures.—A fire caused by an incendiary 
bomb is not different from a fire due to any other cause. It is 
only when dealing with the bomb itself that special precautions 
are necessary. A percentage of incendiary bombs normally con- 
tains high explosives, which usually detonate within 7 minutes 
after impact. Unless known to the contrary, all incendiary 
bombs must be considered to be of explosive type and treated 
accordingly. Ordinary room walls, tables, chairs, and similar 
objects do not provide a safe shield for a hose operator fighting 
such bombs. A brick wall 4y2 inches thick offers adequate pro- 
tection ; whenever the shelter afforded by such walls is available, 
it should be used when combatting incendiaries. Only one fire 
fighter should risk exposure in an attempt to extinguish a bomb; 
do not risk additional casualties. When cover is available, no 
part of the fire fighter’s body should be exposed except the hands. 
Helmets will be worn. When cover is not available, fire fighters 
operate from a nearly prone position and from a distance as 
great as equipment permits. 
c. Employment of equipment.— (1) If the incendiary bomb 
falls close enough to be handled immediately, it may be scooped 
up with a long-handled shovel and thrown to a less combustible 
place. 
(2) If this is not possible, the bomb may be smothered with 
one or two sand mats (par. 7e, app. VI). The fighters should 
then take cover, or run for a distance of 20 yards and lie flat. 
If no detonation occurs within 8 minutes, it can be assumed 
that the incendiary contains no explosive. Sandbags or sand 
mats reduce the fragmentation effect of explosive incendiary 
bombs. Some fragments are confined, and those which do escape 
have substantially reduced speed. 
(3) Whether sandbags or sand mats are placed on the bombs, 
those falling in vital structures should be attacked at once with 
water from hose, pump tanks, knapsack type pumps, or the 
3-gallon decontaminating apparatus operated from behind cover 
or from a prone position at maximum range. 
(4) Fire extinguishers, if available, should be employed in 
the same manner as hose or pump tanks, with due regard for 
their limitations. The soda-acid extinguisher, like all other 
jet type extinguishers, tends to spread burning oil, but can be 
used to control fires adjacent to the burning oil. The carbon 
12 DEFENSE AGAINST CHEMICAL ATTACK 
Figure 134.—Use available cover when fighting small incendiary bombs. Such bombs always must be considered 
explosive. Brick walls offer excellent protection. 
13 BASIC FIELD MANUAL 
Use of protective equipment- 
Small incendiary bombs 
MAY BE SCOOPED UP, 
AND... 
THROWN TO A SAFE 
PLACE, OR... 
MAY BE COVERED WITH 
SAND, SHOVELED INTO A 
BUCKET, 
, „ AND... ' 
DISPOSED OF 1 
Controlling with sand mats— 
Sand mats placed on 
a small explosive in- 
, CENDIARY BOMB - .. 
REDUCE FRAGMENTATION 
EFFECTS'. 
Figure 135. 
14 DEFENSE AGAINST CHEMICAL ATTACK 
Attack bomb with 
STREAM OF WATER. 
OR... 
WITH FIRE EXTINGUISHER FROM 
BEST AVAILABLE CCNER, OR... 
IN ABSENCE OF OTHER EQUIP* 
MENT THROW WATER CN BOMB- 
FROM CANTEEN CUP. OR... 
THROW SAND AROUND 
INCENDIARY BOMB! 
Figure 135. 
tetrachloride extinguisher has limited use against incendiary 
bombs and should not be used in closed places. 
(5) If water barrels and buckets are the only available equip- 
ment for putting water on the blaze, it is best to use a can or 
canteen cup to dip about a pint of water at a time from a bucket 
and throw it on and around the bomb. Utilize the best cover 
available. Throwing larger quantities is likely to cause an ex- 
plosion. (A stream of water thrown on a bomb likewise causes 
an explosion, but the jet forces the flaming particles away from 
the fighter.) 
(6) If other equipment is not available, sand may be thrown 
on the area adjacent to the bomb. This tends to smother fires 
started by the bomb. Sometimes it may be necessary to cover 
the bomb with sand and scoop up the bomb or its molten par- 
ticles with a shovel. In such a ease the bomb or particles may 
15 BASIC FIELD MANUAL 
it 
be placed in a bucket into which a la$fer of sand has previously 
been put. The bomb is then covered with sand and carried 
to a safe point. 
(7) The 400-gallon decontaminating apparatus may be em- 
ployed in much the same manner as regular fire-fighting equip- 
ment if trained operators are available. 
■ 10. Inspection After Incendiary Attacks.—a. General.— 
After an incendiary attack, maintain a watch for several hours 
to make certain that fire does not again break out. 
&, Phosphorus or oil.—When phosphorus or oil bombs have 
been used and the filling is spattered on walls and floors of 
buildings, the liquid must be kept wet and scraped away with 
a hoe, scraper, or knife. Then, as the surfaces dry, they must 
be watched for reignition of remaining incendiary. 
c. Unexploded lomhs.—After each incendiary attack, a care- 
ful inspection must be made for bombs which have not deto- 
nated, and for separated explosive portions which have not 
exploded. 
(1) When such missiles have been located, the spot should be 
marked with a sign, “Unexploded Bomb,” the area roped off, 
and personnel excluded. Under no circumstances will untrained 
personnel handle these “duds.” 
(2) Combustible materials should be removed from the im- 
mediate vicinity to prevent their ignition in case the bomb 
explodes. 
(3) Bomb disposal is a function of the Ordnance Department. 
Bomb-disposal crews should be notified through channels. 
d. Equipment.—Immediately after a fire has been extinguished 
all fire-fighting equipment should be inspected, restored to work- 
ing condition, and returned to its usual place. 
[A. G. 300.7 (19 Feb 44).] 
Bt order of the Secretary of War ; 
Official ; 
J. A. ULIO, 
Major General, 
The Adjutant General. 
G. 0. MARSHALL, 
Chief of Staff. 
Distribution : 
As prescribed in paragraph 9a, FM 21-6; B and H (5) ; 
R (10) ; Bn (5) ; Bn 1 (10) ; C 10. 
For explanation of symbols see FM 21-6. 
16 
U. S. GOVERNMENT PRINTING OFFICE: 194* FM 21-40 
*C 4 
BASIC FIELD MANUAL 
DEFENSE AGAINST CHEMICAL ATTACK 
Changes! 
No. 4 J 
WAR DEPARTMENT, 
Washington 25, D. C., 15 September 1944. 
FM 21-40, 7 September 1942, is changed as follows: 
Terminology of chemical agents is changed as follows. These 
terms should be corrected wherever they occur throughout the 
manual. 
New terminology Old terminology 
Chemical agents: 
War gases: 
Casualty gases: 
Blister gases Vesicants 
Choking gases Lung irritants 
Blood and nerve Systemic poisons 
poisons 
Harassing gases; 
Vomiting gases Irritant smokes or sternutators 
Tear gases Lacrimators 
Screening smokes 
Incendiaries 
B 5. Definitions (Superseded).—a. Chemical agents are sub- 
stances used in war which, through their chemical properties, 
produce— 
Injurious or irritant effect on personnel. 
Screening smoke. 
Incendiary action. 
’These changes supersede section III Training Circular No. 67, War Department, 
1943; information on nitrogen mustards and titanium tetrachloride as added by 
Cl to table on “Vesicants.” 
AGO 311D 598804°—44 1 FM 21-40 
C 4 
BASIC FIELD MANUAL 
b. War gas is a chemical agent which has an injurious effect 
on the body, of which harasses personnel. 
Note.—The first chemical agents were literally gases—that is, they were in a 
gaseous state; hence the origin of terms such as “gas mask.” These terms were 
short and convenient, so they continued in use even after introduction of such chem- 
ical agents as mustard gas (which is liquid at ordinary temperatures) and irritant 
smokes (which are finely divided solid particles). To the chemist, “war gas” is a 
misnomer if applied to mustard gas, and “liquid blister gas” is a contradiction in 
terms. But in its war application, “war gas” (or even “gas”) is a specialized military 
term, sanctioned by long use. It is so used in this and other War Department 
publications. 
. c. Chemical warfare symbols are letters or combinations of 
letters and numerals designated by the War Department for 
convenience, to be used in place of full names of chemical agents. 
Some symbols have been changed recently in the interest of 
uniformity. Only current symbols are used in these changes. 
d. Concentration refers to the amount of a war gas or screening 
smoke in a unit volume of air. It is usually expressed in ounces 
of substance per 1,000 cubic feet of air (numerically the same as 
milligrams per liter). , 
e. Hydrolysis is the reaction of any chemical substance with 
water to form new substances. This reaction is important in 
chemical warfare because— 
(1) Many war gases are thereby rendered harmless. (But if 
the product of hydrolysis is itself a poison, as with gases contain- 
ing arsenic, further effort is required to make the product harm- 
less.) 
(2) Some screening smokes depend to a considerable extent 
on hydrolysis for their obscuring effect. 
/. Contamination is the process of spreading an injurious war 
gas. Personnel, objects, or terrain may be contaminated. 
g. Decontamination is the process of removing or destroying 
• chemical agents, or of changing them into harmless substances. 
Only persistent gases need be decontaminated, and, generally speak- 
ing, only blister gases are persistent. ' 
2 
AGO 311D FM 31-40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
■ 6. (Superseded) Classification of Chemical Agents.— 
Chemical agents are classified in four ways: 
a. By 'physical state. 
Solid Liquid Gas 
Note.—This classification is based on the state of the substance under field 
tions in temperate weather. 
b. By tactical use. 
Casualty gases— 
Harassing gases— 
Screening smokes— 
Incendiaries— 
Are capable of 
producing serious 
injury or death in 
ordinary field con- 
centrations. 
Force masking 
and slow operations. 
Only those which 
produce this result 
with a small quan- 
tity of munition are 
considered primar- 
ily as harassing 
gases. 
When burned, 
h. drolyzed, or atom- 
ized, produce a 
dense, obscuring 
smoke, used to deny 
hostile observation 
and reduce effective- 
ness of enemy’s 
aimed fire. 
Are used pri- 
marily for setting 
fire to materiel. 
They may pro- 
duce casualties 
from bums. 
Note.—Many chemical agents have more than one tactical use. The most im- 
portant use determines the primary classification. 
c. By effect on body. 
Blister gases (sometimes called vesicants) 
are readily absorbed by both exterior and 
interior parts of body, causing inflammation, 
blisters, and general destruction of tissue. 
Blister gas vapors attack respiratory tract 
much as choking gases do, although effects 
are usually more severe in upper tract. Eyes 
are very susceptible. 
Choking gases (sometimes called 
lung irritants) cause irritation and 
inflammation of bronchial tubes and 
lungs. Their primary physiological 
action is limited to respiratory tract, 
injury extending to deepest part of 
lungs. 
AGO 31 ID 
3 FM 31-40 
C 4 
BASIC FIELD MANUAL 
Blood and nerve poisons 
(sometimes called systemic 
poisons) cause injury after 
they are absorbed into 
blood stream. 
Vomiting gases (sometimes 
called irritant smokes or s(er- 
nuiators) cause coughing, 
sneezing, pain in nose and 
throat, nasal discharge, and 
sometimes tears, often fol- 
lowed by headache. 
Tear gases (sometimes 
called lacrimators) cause 
copious flow of tears and 
intense, although tempo- 
rary eye pain. 
Note.—The physiological classification omits screening smokes and incendiaries; 
however, white phosphorus (as an incendiary) and other incendiaries produce casual- 
ties. 
d. By persistency.—“Persistency” means length of time a war 
gas normally remains effective in the open at point of dispersion. 
“Effective” means gas is capable of producing casualty or other 
intended effect on unprotected personnel. 
Nortpersistent gases are those nor- 
mally effective in the open, 10 min- 
utes or less at the point of dispersion. 
Persistent gases are those normally effective 
in the open at point of dispersion more than 
10 minutes. 
Further division; 
Moderately persistent (10 minutes to 12 hours). 
Highly persistent (more than 12 hours). 
Note.—Persistency usually decreases as rate of-vaporization increases. Vaporiza- 
tion increases with heat, wind, and fineness of dispersion. Thus any given persistent 
gas is apt to be less persistent in hot weather, when exposed to wind, or when dis- 
persed as fine spray. Even nonpersistent gases may persist for hours when collected 
’ in low, sheltered places and favored by cold, dampness, and still air. 
■ 7. (As changed by C 1 and C 3) (Superseded) General 
Description of Chemical Agents.—a. General.—Descriptions 
given below are limited to features important in field identifica- 
tion. It should be noted that descriptions are of chemical agents 
developed by United States armed forces which are not neces- 
sarily identical with chemical agents the enemy may use. 
b. Detection.—(1) Odors characteristic of chemical agents are 
likened below to generally known odors, but the individual may 
not always agree with these descriptions. Sensory reactions vary 
greatly; therefore, each man must learn how each chemical agent 
smells to him. Methods of training in identification, using the 
detonation gas identification set and the so-called “sniff set,” are 
given in paragraph 8, and in TM 3-305. FM 31-40 
c 4 
DEFENSE AGAINST CHEMICAL ATTACK 
(2) Modification of odors is to be expected in combat. Enemy 
counterparts of United States chemical agents may have odors 
which differ from ours, either because of manufacturing methods 
or intentional “masking” of odors. Intermingling battlefield 
odors also may distort characteristic odors; moreover, sensitivity 
to odors decreases with repeated exposure. 
■ 7.1. Description of Blister Gases (Added).—Blister gases 
are used for their casualty effect (or for the threat of casualties) 
by which normal use of ground may be denied, movements slowed, 
supply impeded, and use of materiel or installations prevented 
pending decontamination. Physiologically, they injure the eyes 
and lungs, and blister the skin. Troops should remember that , 
enemy blister gases may not smell like ours and may even be 
odorless; therefore, detector devices provide the only reliable 
method of warning. Enemy gases also may differ from ours in 
persistency; for example, there are several varieties of nigrogen 
mustards which make it possible to deny normal use of ground 
for a long or short time, according to the enemy’s plans. Blister 
gases include: 
Physical state 
Odor 
Persistency 
Mustard Oas (H) 
Normally dark brown 
liquid, changing slowly to 
colorless gas. 
Like garlic or horse- 
radish when impure; 
pure H may be nearly 
odorless. 
High in winter; 20 days 
or more, since it vaporizes 
slowly. Less in summer; 
sometimes only 1 day. 
Solidifies below 45° F. 
Nitrogen Mustards (UN) • 
Some are liquid at normal 
temperatures; others are 
slow-melting solids. Color- 
less to pale yellow. 
Faint to odorless; at 
strongest, like fish or 
soft soap. 
Volatility (tendency to 
vaporize) varies greatly. 
Least volatile may persist 
for weeks, others as short 
a time as 1 hour. 
•Note.—This is a “family” of war gases like H in some ways. HN’s are chem- 
ically related to each other but differ in physical state, odor, persistency, and effect. 
5 FM 31-40 
C 4 
basic field manual 
Physical state 
Odor 
Persistency 
Lewisite (L) 
Colorless liquid when 
pure, but usually dark 
brown, oily liquid. Evap- 
orates as colorless gas. 
Odorless when pure; 
like geraniums when 
impure; always irritat- 
ing to nose and throat. 
Less than H, usually 1 to 
7 days. Hydrolyzes in 
wet weather to lewisite 
oxide, a white solid which 
blisters skin after extended 
contact. 
Ethyldichlorarsine (ED) 
Clear, somewhat oily liq- 
uid when pure, but usually 
brown liquid vaporizing as 
colorless gas. Slightly solu- 
ble in water. 
“Fruity” and irritat- 
ing. 
Moderate; effective 1 to 
12 hours, depending on 
weather, terrain, and con- 
centration. Slow hydrol- 
ysis, forming poisonous 
product. 
Methyldichlorarsine (MD) 
Colorless liquid, vaporiz- 
ing as colorless gas. 
Burning or irritating. 
Same as ED (above). 
Phenyldichlorarsine (PD) 
Clear liquid. 
Irritating. 
Same as ED (above). 
■ 7.2. Description of Choking Gases (Added).—Choking 
gases injure unprotected men chiefly in the respiratory tract— 
that is, the nose, throat, and particularly the lungs. In extreme 
cases, membranes swell, lungs become filled with liquid, and 
6 
AGO 311D FIVE 21-40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
death results from lack of oxygen. The important choking 
gases are; 
Physical state 
Odor 
Persistency 
Phosgene (CO) 
Clear liquid at low tempera- 
tures; gas in warm weather 
unless under pressure. White 
mast when released, turning 
colorless. 
Sweet in low concen- 
trations; pungent (like 
freshly cut corn or new- 
mown hay) in high con- 
centrations. 
Nonpersistent; is dissi- 
pated on high terrain 
in 10 minutes or less. 
Chlorpicrin (PS) 
Colorless, oily liquid. 
White gas when released, 
turning colorless. 
Sweet, like flypaper. 
Moderate, 1 to 12 
hours. 
■ 7.3. Description of Blood and NErve Poisons (Added).— 
There are three principal gases in this category, namely: 
Physical state 
Odor 
Persistency 
Hydrocyanic Acid 
Clear, colorless liquid, 
changing to colorless gas. 
Faint, undetectable 
to some; like peach ker- 
nels or bitter aknonds. 
Nonpersistent; lighter 
than air but cooled by 
rapid vaporization and 
thus temporarily and 
locally heavier than air. 
Arsine 
Colorless gas. 
Practically 
when pure; 
garlic-like, 
taste.) 
odorless 
otherwise 
(Metallic 
Nonpersistent. 
Cyanogen Chloride 
Colorless liquid, vaporiz- 
ing on release to form color- 
less gas about twice as heavy 
as air. 
Practically odorless; 
sometimes biting. 
Nonpersistent. 
AGO 311D 
7 FM 21-40 
C 4 
BASIC FIELD MANUAL 
■ 7,4, Description of Vomiting Gases (Added).—Vomiting 
gases are normally solids, vaporizing when heated to form toxic 
smokes valuable for harassing; when released indoors they may 
cause serious illness or death. Principal vomiting gases are: 
Physical state 
Odor 
Persistency 
Diphenylaminechloraraine 
(Adamsife) (DM) 
Yellow or green crystal solid 
in pure state, vaporizing when 
heated into yellow smoke. 
Practically odorless. 
Nonpersistent; lasts 
about 5 minutes at point of 
release. 
Diphenylchlorarsine (DA) 
White solid in pure state, 
vaporizing under heat into 
fine white smoke. 
Practically odorless. 
Nonpersistent: lasts less 
than 10 minutes at point of 
release. 
Diphenylcyanarsine (DC) 
Colorless, crystal solid, va- 
porizing under heat into white 
smoke. 
Resembles garlic 
and bitter almonds. 
Same as DA (above). 
■ 7.5. Description of Tear Gases (Added).—Tear gases are 
used for harassing purposes, producing tears, and irritating the 
skin. Principal tear gases are; 
Physical state 
Odor 
Persistency 
Chloracefophenone (CN) 
Solid, converted by heat hi- 
Like apple blossoms. 
Persistent as solid; non- 
to colorless gas. 
persistent as gas. 
8 
AGO 311D EM 21-40 
C 4 
defense against chemical attack 
Physical state 
Odor 
Persistency 
Chloracetophenone Solution 
(CNS) 
Solid CN dissolved in mix- 
ture of chloroform and chlor- 
picrin. White gas when re- 
leased, becoming colorless. 
Same as CN (above). 
Summer: Up to 1 hour 
in open, 2 hours in woods. 
Winter: Up to 6 hours in 
open and 1 week in woods. 
Brombenzylcyanide (BBC) 
Brown, oily liquid, evapo- 
rating into gas. 
Like sour fruit. 
Summer: Up to 3 days 
in open and 7 days in 
woods. Winter: Up to 20 
days. 
■ 7.6. Description of Screening Smokes (Added).— 
Screening smokes are used both defensively and offensively. 
Smoke consists either of finely divided solid particles or liquid 
droplets suspended in the atmosphere. Smoke is injurious if 
heavy concentrations are breathed a relatively long time. 
Therefore, the soldier wears a gas mask in smoke when; 
—He feels unpleasant effects (some men are more sensi- 
tive to smoke than others). 
—Close downwind from source of smoke. 
—Smoke is released indoors. 
Smoke is used to camouflage war gases; therefore the soldier 
wears his mask whenever the enemy uses smoke, until it is 
determined that the smoke does not conceal a war gas. Principal 
screening smokes are: 
Physical state 
Miscellaneous 
Sulfur Trioxide—Chlorsulfonic Acid 
Solution (FS) 
Liquid, hydrolyzing rapidly in air to 
form dense white smoke cloud. 
Generally used for airplane spray. 
Corrodes metal and injures fabrics. 
AGO 311D 598804*—44——2 
9 FM 21-40 
C 4 
BASIC FIELD MANUAL 
Physical state 
Miscellaneous 
Titanium Tetrachloride (FM) 
Colorless liquid atomized by spray or 
detonation to form white smoke. 
Obscuring power slightly less than 
FS. Used in same way as FS. 
Ilexachlorethane Mixture (HC) 
Solid; produces dense white smoke when 
burned. 
Used in smoke pots: high obscuring 
power. Service gas mask carrier may 
break down under prolonged use in 
HC smoke; self-contained oxygen mask 
necessary. 
White Phosphorus (TCP) 
White or amber solid, igniting spon- 
taneously on exposure to air, making dense 
white smoke. 
Most effective screening smoke; 
secondary use as incendiary and war 
gas. 
Special Oil 
This is used in mechanical smoke generators. In one model, 
steam is shot into cold oil; the two are superheated, then ejected 
to become a thick fog upon contact with atmosphere. In 
another model, water and oil are mixed before heating. 
■ 7.7 Description of Incendiaries (Added).—Incendiaries 
are used to ignite combustible material, but may also injure 
personnel. Combinations of incendiaries are sometimes used. 
American incendiary bombs are described in TM 9-1980, 
“Bombs for Aircraft.” Common incendiaries are: 
Thermit (TH) 
Normally used as igniter in magnesium bombs; also in large 
thermit bombs which are virtually uncontrollable. 
10 
AGO 311D FM 21-40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
Physical properties 
Burning 
Control 
Intimate mixture of iron 
Aluminum reacts with 
Resulting fires should 
oxide, aluminum, barium 
iron oxide and generates high 
be combatted, not bomb 
nitrate, and small amounts 
of sulfur and castor oil. 
temperature (4,300° F.), pro- 
ducing molten iron. Burns 
with orange glow, quickly 
and violently. 
itself. 
Magnesium 
Used for cases of small incendiary bombs; powder form used 
as ingredient of gel mixture for large incendiary bombs. 
Physical properties 
Burning 
Control 
Metallic (solid or pow- 
der). 
Magnesium case in 4- 
pound bomb burns 10 to 
16 minutes at about 3,600° 
F. Has intense white glow 
and emits white harmless 
smoke. 
Burns faster when water 
is used, but explodes when 
jet of water is applied; result- 
ing fragments are quickly ex- 
tinguished. Small bombs 
best extinguished by drop- 
ping in pail of water. 
White Phosphorus (WP) 
Unsatisfactory incendiary because of low burning temperature, 
but ignites readily flammable materials, especially dry vegeta- 
tion; often used in so-called “calling cards” dropped on forests, 
etc. Effective against personnel, causing painful burns; large 
fragments may kill. 
Physical properties 
Burning 
Control 
See paragraph 7.6. 
Burns with bright 
Stops burning when 
yellow flame, giving ofl 
flooded with water, but re- 
white smoke. 
ignites when water evap- 
orates; copper sulphate so- 
lution stops burning of 
particles clinging to flesh. 
AGO 31 ID 
11 EM 21-40 
C 4 
BASIC FIELD MANUAL 
Oil (SR, CR, LA) 
Used extensively by Japanese. Little used by United States. 
Physical properties 
Burning 
Control 
Gasoline with coconut oil 
and rubber thickener. Small 
pieces of metallic sodium 
sometimes added to prevent 
easy extinguishing. 
Has yellow flame; 
emits dense black smoke. 
Should be attacked with 
any fire extinguisher or 
smothered with blankets, 
dirt, or sand. Water is 
used on resulting fires, but 
not directly on oil. 
Gasoline Gels (NP, IM) 
Used extensively by United States as filling for bombs, gre- 
nades, and flame throwers. 
Physical properties 
Burning 
Control 
Thickened gasoline, often 
Burns with yellow 
Smothering with earth 
looking like rubber cement. 
flame; produces a dense 
best control. Water may 
black smoke. 
also be used. 
■ 9. (As changed by Cl and C3) (Superseded) First Aid for 
Gas Casualties.—a. General.—Protective equipment reduces 
the hazard from field concentrations of war gases to a minimum. 
Effects of gases on unprotected personnel depend primarily on 
two factors; 
(1) Concentration and time of exposure. (Long exposure to 
a weak vapor concentration usually has the same effect as short 
exposure to a heavy concentration.) 
(2) Susceptibility of the individual. (Different soldiers show 
varying sensitivity to the same gas.) 
b. Responsibility.—Personal decontamination is the individual 
soldier’s responsibility. So is first aid. Decontamination 
promptly and properly performed prevents needless injury and 
enables men who would otherwise be casualties to perform their 
usual duties. 
12 
AGO 311D FM 21-40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
c. Disposition of exposed personnel.—Immediate disposition is 
a command decision. Considering the tactical situation, sever- 
ity of exposure as known to him, and the medical officer’s recom- 
mendation, the unit commander decides whether exposed per- 
sonnel should be continued in action. The need for evacuation 
is often obviated in nonpersistent gas attacks if masks have 
been adjusted properly, since these gases are dissipated in a 
very short time. 
■ 9.1. Equipment (Added).—a. For individual protection, the 
soldier has protective clothing, shoes treated with impregnite, 
gas mask, eyeshields, and protective covers. The gas mask pro- 
vides ample protection against nonpersistent gas in normal field 
concentrations; other items are needed for protection against 
blister gases. 
Note.—His mask is the soldier’s best protection. It is always adjusted first, 
before administering first aid, unless the face and eyes are contaminated. Such con- 
tamination is always removed before masking, even in a contaminated area. 
b. For individual first aid, the soldier is issued protective oint- 
ment and BAL eye ointment. In addition he may carry soap to 
wash contaminated skin and may use his first-aid kit to take care 
of incendiary burns. 
c. For organizational first aid, the gas casualty first-aid kit is 
issued on the basis of 1 kit per 25 men, each kit containing an 
instruction sheet. Contents of the kit are: 
Item 1. Chloroform, U. S. P. 
Item 2, Calamine lotion with 1 percent phenol and 1 
percent menthol. 
Item 3. Copper sulfate, 10 percent solution. 
Item 4. Eye and nose drops. 
Item 5. Eye solution, BAL. 
Item 6. Cotton pads. 
Item 7. Amyl nitrite, U. S. P. 
Item 8. BAL ointment (two tubes). 
Item 9. Protective ointment. 
AGO 311D 
13 EM 21-40 
C 4 
BASIC FIELD MANUAL 
■ 9.2. Blister Gases (Added).—a. General.—Blister gases, as 
a group, have many characteristics in common. These include— 
(1) Action. Blister gases burn and blister any area of the 
body they contact, either in liquid or vapor form. 
(2) Effectiveness. A drop the size of a pinhead produces a 
blister the size of a quarter. An unmasked man exposed 1 hour 
to a few parts of vapor per million parts of air can become a 
casualty. All blister gases have marked effect on the eyes. 
(3) Penetration of body. Blister gases are absorbed by skin, as 
ink soaks into a blotter. 
(4) Insidious character. H and HN can “creep up” without 
warning, since they sometimes have no odor and cause no 
immediate pain. No sign of injury may appear for 2 to 4 hours. 
(L usually irritates the skin, eyes, and respiratory tract im- 
mediately, however, and liquid L stings the skin within a minute 
or two.) 
h. First-aid procedure.—(1) Eyes are given first attention 
before the mask is adjusted, even if the victim is still in a con- 
taminated area. Contaminated portions of clothing (ordinary 
or protective) may be cut away, or garments removed entirely 
if grossly contaminated. 
(2) Vapor burns to skin, eyes, or respiratory tract cannot be 
decontaminated successfully 
(3) Liquid burns demand fast action; first aid is much less 
effective when applied after the first 2 or 3 minutes. Measures 
are taken in the following sequence; 
Care for eyes. 
Decontaminate hands. 
Decontaminate face, neck, and ears. 
Adjust gas mask. 
Decontaminate other parts of body. 
Take care of personal equipment. 
Procedures for blister gases are outlined in the following chart: 
14 
AGO 311D FM 31-40 
C 4 
Area 
affected 
Mustard gas and nitrogen mustards 
Lewisite and other arsenieals (Ethyldichlorarsine, 
Methyldichlorarsine, and Phenyldichlorarsine) 
Physiological Effects 
Physiological Effects 
E 
H; Vapors cause no immediate symptoms; even liquids 
L: Eyes are especially susceptible. Vapor irritates 
are only mildly irritating at flrsf. In a few hours eyes 
immediately; liquid causes instant, excruciating pain and 
become Inflamed, smart, water, feel gritty, and are sensi- 
spasm of eyelids. Unless first-aid measures are taken 
tive to light. Lids swell. In severe cases there is great 
immediately, eyes swell and inflame seriously within 
pain, tears, and yellow discharge—permanent damage may 
1 hour, and may be permanently injured. 
result. 
ED, MB, PD: Same as lewisite, but generally less 
Y 
NN: Generally the same as H, but damage from more 
volatile forms of HN is more severe. 
severe. 
First aid 
First aid 
Flush with water immediately. Flushing is very helpful 
Apply BAL eye ointment at once, either for liquid or 
if done in first minute after contamination, but valueless 
vapors severe enough to cause pain and spasm of the lids. 
E 
after 2 minutes. To flush, hold face upward, opening in- 
If lids can be opened, squeeze ointment directly into eye 
jured eye by pulling on lower lid with one hand, and 
and massage lids gently; if not, apply to closed eye and 
pouring water from container held in other. Have patient 
rub into slit between lids. As soon as pain lessens and eye 
move eye from side to side, and up and down. Continue 
can be opened, apply more ointment. Also rub it on 
washing for to 2 minutes. If no water is available, use 
eyelashes, lids, and skin around the eye. If no BAL eye 
urine or Item 4 (eye and nose drops) from gas casualty 
ointment is available, use BAL eye solution (Item 6 in 
S 
first-aid kit. 
gas casualty first aid kit). Open eye, place two to four 
drops in it, and one or two drops on eyelids. Apply only 
once. Caution: Do not use BAL eye ointment or solu- 
tion unless eyes are painfully affected by arsenical blister 
gas; it causes temporary irritation, but is not injurious. 
DEFENSE AGAINST CHEMICAL ATTACK 
AGO 31 ID 
15 EM 21-40 
C 4 
EM 31-40 
C 4 
BASIC FIELD MANUAL 
s 
K 
Physiological Effects 
H: Injury begins with reddening, like sunburn, and may 
be followed by blistering (under different climatic condi- 
tions, this varies with concentration and length of expos- 
ure) . Liqu id always blisters unless counteracting steps are 
taken at once. Normally moist skin areas are most af- 
fected (like bend of elbows and knees, armpits, and crotch). 
HN: Vapor about one-fifth as damaging as n. Liquid 
forms blisters more quickly, but they are less severe. 
Physiological Effects 
Same as H, but liquid acts faster, penetrating skin 
rapidly and causing stinging sensation within 1 or 2 
minutes; vapor far less dangerous than n vapors. 
First Aid 
First Aid 
H: Liquid must be removed and skin decontaminated 
Liquid is blotted from skin immediately. If skin 
within 3 minutes to avoid blistering. Remove contam- 
hurts, gas may be assumed to be an arsenical. Apply 
I 
inated clothing. Then blot skin with absorbent material 
protective ointment as described for H bums (although it 
furnished with protective ointment, or with dry cloth. Be 
may not completely prevent blistering if weather is hot). 
careful not to contaminate additional skin while blotting. 
Use soap and water if nothing else is available. Attempt 
Next, squeeze protective ointment from tube, rubbing it on 
to prevent blisters from breaking; leave them for medical 
affected area about 15 seconds. Wipe ofl excess ointment. 
treatment. Vapor burns cannot be helped by first aid. 
N 
Repeat this procedure if skin has been heavily splashed. 
Note.—When gas casualty first-aid kit is available, 
Soap and water can be used as a substitute, or bleach paste 
BAL eye ointment from the kit may be used on the skin. 
(equal quantities of water and dry bleach) can be used if 
But the individual soldier’s small tube of BAL eye oint- 
. washed ofl within 3 minutes. 
ment is used only for contaminated eyes. 
DEFENSE AGAINST CHEMICAL ATTACK 
Area 
affected 
Mustard gas and nitrogen mustards 
Lewisite and other arsenicals (Ethyldichlorarsine, 
Methyldichlorarsine, and Phenyldichlorarsine) 
R 
Physiological effects 
Physiological effects 
E 
Respiratory system. Vapors inflame throat and windpipe 
L: Same as II. 
S 
if breathed. Mouth becomes dry, throat burns, and harsh, 
ED, MD, PD: Same as H, generally, but breathing 
P 
distressing cough develops. Partial loss of voice is common. 
very low vapor concentrations may cause coughing, 
I 
Pneumonia may develop in severe cases. 
sneezing, pain in nose and throat, nausea and vomiting, 
R 
Digestive system. Nausea and vomiting may follow severe 
and distressed feeling. 
A 
skin contamination, especially in hot weather, even if mask 
T 
has been worn. This is a systemic effect not due to direct 
0 
injury; swallowing of contaminated saliva, food, or drink 
R 
may cause inflammation of stomach, pain, and vomiting. 
AND 
First aid 
First aid 
D 
Same for both respiratory and digestive tracts. Remove 
L: Same as H. 
I 
liquid gas from face immediately to prevent further in- 
ED, MD, PD: Generally the same for n, but after 
G 
halation of vapors. Also remove contaminated clothing. 
exposure to low vapor concentrations (producing 
E 
No other first aid is effective. Victim is handled like 
symptoms like those of vomiting gas), rinse nose and 
S 
choking gas casualty: loosen clothes, keep quiet and warm, 
throat with water, and keep patient quiet. Fumes of 
T 
give warm (nonalcoholic) drink, and evacuate by litter. 
chloroform (Item 1 in gas casualty first-aid kit) may be 
I 
If no medical treatment is available and evacuation is im- 
inhaled to give relief in severe cases, inhalation being 
V 
possible for 24 hours or longer, give wound tablet from 
repeated as required. 
E 
SYSTEMS 
first-aid pouch to prevent pneumonia. 
AGO 311D 
AGO 31 ID FM 21-40 
C 4 
Area 
affected 
Mustard gas and nitrogen mustards 
Lewisite and other arsenicals (Ethyldichlorarsine, 
Methyldichlorarsine, and Phenyldichlorarsine) 
S 
First Aid—Continued 
Don’t use either ointment or bleach if skin has already 
reddened or begun to blister; it only increases the burn. 
Instead, use calamine lotion (Item 2 in the gas casualty 
first-aid kit), following instructions given in kit. Vapor 
burns cannot be helped by first aid; the damage is already 
M5 PROTECTIVE OINTMENT 
All references to protective ointment noted above 
apply to M4 ointment. 
M4 ointment will be replaced by M5 ointment, now in 
K 
done, and neither ointment nor soap and water helps. 
HN: Liquid burns are treated with ointment in same 
manner as H liquid burns. But ointment merely dilutes 
and does not destroy HN. Therefore, wash off film of oint- 
ment with soap and water preferably, or with water alone. 
production. M5 ointment is used exactly as M4 oint- 
ment with these exceptions: 
(1) On applying M5 ointment to contaminated skin, 
rub it in for 30 seconds instead of 15 seconds. 
(2) Leave it on the skin. 
I 
Don’t use ointment if skin is already red; instead, use soap 
and water. Vapor burns cannot be helped by first aid, since 
damage is already done. 
Note.—If blisters develop from either H or HN burns, 
try to prevent them from breaking until medical treatment 
(3) M5 ointment is used before exposure to blister gas, 
as well as after. Using the entire contents of one tube, 
rub ointment in a smooth, even coating on unprotected 
skin areas. Apply again whenever absence of the char- 
acteristic color (gray green) indicates the skin is no longer 
N 
is available. 
protected. Before-exposure protection ei tends only to blister 
gas vapor; if droplets fall on skin, decontamination must be 
accomplished as directed in above tables. 
BASIC FIELD MANUAL 
18 
AGO 811D FM 21—40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
Physiological effects 
First aid 
Symptoms vary considerably, but there 
is usually irritation of nose and throat, 
coughing, difficulty in breathing, and pain 
in chest, especially upon deep inhalation. 
Other possible symptoms are tears, vomit- 
ing, sweating, easy fatigue, and blueness 
of lips and ear lobes. Symptoms appear 
immediately only if exposure has been se- 
vere. They may persist and grow worse: 
but often first symptoms disappear, fol- 
lowed by latent period in which victim 
feels fairly well. More serious symptoms 
of lung injury may not appear for several 
hours. 
Keep mask adjusted until area is free 
of gas. Soldier should carry on if there 
are no immediate symptoms. But if 
there are immediate symptoms, insti- 
tute first aid as soon as tactically pos- 
sible. Loosen clothing, have soldier 
rest, and keep him warm with blankets. 
Do not give artificial respiration. Offer 
nonalcoholic, stimulating drinks (hot 
tea or coffee). Evacuate to aid station 
by litter as soon as possible. Greatest 
danger for choking gas victims is during 
first 48 hours after exposure. 
9.3. Chokino Gases (Added). 
9.4. Blood and Nerve Poisons (Added). 
Physiological effects 
First aid 
Hydrocyanic acid or cyanogen chloride 
Highly toxic when inhaled. High 
concentration is fatal (labored breath- 
ing, convulsions, coma, then death). 
Low concentration- may produce head- 
ache, dizziness, and nausea. First 
breath may so stimulate respiration 
that it is impossible to hold breath. 
Liquid penetrates the skin and is 
toxic. 
If victim is in a closed place, mask him and 
move into fresh air immediately; too great 
a concentration may penetrate the gas mask 
canister. If he has stopped breathing, give 
artificial respiration until medical aid is 
available. Use amyl nitrite (Item 7 of gas 
casualty* first-aid kit) meanwhile. Crush 
and hold close to victim’s nose or thrust 
inside facepiece if masked. Repeat at 3- 
to 5-minute intervals, meanwhile continu- 
ing artificial respiration. If liquid gets on 
skin, wash with water or a weak solution of 
baking soda and water. Remove clothes 
containing liquid, and let them air. 
Arsine 
Mild cases cause lassitude, headache, 
and uneasiness. Increased exposure 
causes chills, nausea, and vomiting. 
Severe exposure damages blood, causing 
anemia; urine is brown or red. 
Adjust mask and remove victim by litter 
to fresh air. Do not let him walk. Hos- 
pitalize immediately. 
AGO 31 ID FM 21-40 
C 4 
BASIC FIELD MANUAL 
9.5. Vomiting Gases (Added) 
Physiological effects 
First aid 
Irritate nose and throat, often caus- 
ing coughing, sneezing, and salivation. 
Pain in nose, throat, and windpipe is 
fairly intense; gums and teeth ache. 
Nausea and vomiting may occur, and 
victim may feel very distressed. But 
there is little danger, and effects usually 
pass within 3 hours. Most victims 
can carry on strenuous duties without 
harm, and often with a more rapid de- 
crease in symptoms. 
Keep mask adjusted as long as gas is 
present in atmosphere, removing it only 
briefly during periods of actual vomiting. 
Remove, shake, and air outer clothing if 
situation permits. Wash skin with soap 
and water. If symptoms persist, rinse nose 
and throat with water. In extreme cases, 
keep victim quiet until distressing symp- 
toms have passed, and have him inhale 
fumes of chloroform (Item 1 in gas casualty 
first-aid kit). Repeat inhalations as 
required. 
9.6. Tear Gases (Added) 
Physiological effects 
First aid 
Produce acute pain in eyes, profuse 
tears, and spasm of eyelids. There is 
usually no permanent damage, and 
effects wear off quickly; but tempo- 
rarily victim may find it almost im- 
possible to see. 
Do not rub eyes; this only increases the 
irritation. Keep mask adjusted until at- 
mosphere is free of gas, then remove it and 
face into wind with eyes open. Skin areas 
which sting or burn, or on which liquid gas 
has been splashed, should be washed with 
soap and water. If liquid has entered eyes, 
flush them with plenty of water, or use eye 
and nose drops (Item 4 in gas casualty 
first-aid kit). Medical treatment is not 
ordinarily needed, nor is evacuation nor- 
mally necessary. 
20 
AGO 311D FM 21-40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
9.7. Screening Smokes (Added). 
Physiological effects 
First aid 
Liquid smokes 
Liquids irritate or burn skin. Smoke 
itself is usually harmless except in pro- 
longed exposure; slightly irritating to 
respiratory tract. 
Wash liquid from body with water (pref- 
erably soapy). If respiratory tract is irri- 
tated by smoke, move to fresh air when 
tactically possible. 
Solid smoke {HO 
Prolonged exposure without mask 
irritates nose and throat; may cause 
coughing and lung irritation. 
Remove victim to fresh air if tactically 
possible. 
White phosphorus 
Smoke is harmless except in pro- 
longed exposure, but burning particles 
cause severe burns. 
Immerse affected skin area in water to 
extinguish burning particles. Exclude air 
from particles until they can be removed; 
otherwise, they reignite. Try to wipe or 
brush particles from skin with wet cloth. 
(Medical aid may be required for this.) 
Apply copper sulfate (Item 3 in gas casualty 
first-aid kit) to burned area for several 
minutes. This coats particles, keeping 
them from air, and permits exposure of 
burn without danger of fire. Particles can 
then be removed more easily, preferably 
with forceps. Caution: Do not use grease, 
oils, or ointments; phosphorus poisoning 
may result. 
AGO 31 ID 
21 I’M 21-40 
<2 4 
BASIC FIELD MANUAL 
Physiological effects 
First aid 
White phosphorus burns are dis- 
cussed under screening smokes (par. 
14). Other incendiaries cause ordinary 
burns. 
If skin is broken, cover raw area with 
first-aid dressing. For more serious burns, 
give victim first aid , for shock, keep quiet 
and warm, and evacuate as soon as possi- 
ble. 
9.8. Incendiaries (Added). 
■ 126. Personal Protective Measures (As changed by 
C 1).—a. Protective ointments Ml, M2, M3, and M4.—Protec- 
tive ointments will * * * skin,” are rescinded. 
AGO 311D EM 21—40 
C 4 
DEFENSE AGAINST CHEMICAL ATTACK 
Appendix VII (Added) 
PROTECTION AGAINST CHEMICAL SPRAY ATTACK 
■ 1. General.—The following procedure for protection against 
chemical spray attack (based upon present knowledge as gained 
through tests) is fundamental, is intended only as a guide, and 
may vary according to local conditions. The procedure as modi- 
fied locally will be made a part of the SOP for defense against 
air attack. 
■ 2. Eyeshields,—Eyeshields will be worn at all times in the 
open when spray attack is likely. 
■ 3. Warning of Airplane Spray Attack.—When attacking 
aircraft are actually observed to begin a spray attack, only the 
warning cry of “SPRAY!” will be given. 
■ 4. Protective Cover.—For additional information see TM 
3-290. 
a. Procedure for use.—(1) Immediately put on protective 
cover on hearing the cry of “SPRAY!” and follow SOP for 
defense against air attack (if firing, thrust rifle or carbine for- 
ward through top corner of protective cover). 
(2) While under the cover (worn for the brief period in which 
spray is falling and droplets are in the air), remove eyeshields, 
decontaminate facd and hands, and adjust gas masks. Test 
for spray by means of detector paper before removing covers. 
(3) After removing covers and as soon as the tactical situa- 
tion permits, men inspect one another for evidence of con- 
tamination, and carry out further personal decontamination 
where necessary. Speed in personal decontamination is essen- 
tial. Discard cover, and if possible destroy it, after exposure 
to a spray attack. 
b. Procedure if contaminated.—Frequently, in surprise spray 
attack, there will not be time to adjust protective covers quickly 
AGO 31 ID 
23 FM 21-40 
C 4 
BASIC FIELD MANUAL 
enough to avoid becoming contaminated. When this occurs, 
the following instructions will be observed: 
(1) Do not attempt to adjust protective cover, but follow 
SOP for defense against air attack. 
(2) When spray has ceased to fall, discard eyeshields. 
(3) Carry out personal decontamination as soon as the tactical 
situation permits. 
(4) Adjust gas mask if remaining in the sprayed area. 
c. Caution.—(1) After a spray attack, care must be exercised 
in passing through contaminated vegetation. 
(2) Personnel, after having their clothing sprayed even 
lightly, will avoid closed places for at least 4 hours, or until 
clothing is removed. 
d. Specially designated personnel. The protective cover will 
not be used when it interferes with normal functions of an essen- 
tial task of specially designated personnel. 
[A. G. 300.5 (17 Feb 44).] 
By order of the Secretary of War; 
G. C. MARSHALL, 
Chief of Staff. 
Official: 
J. A. ULIO, 
Major General, 
The Adjutant General. 
Distribution; 
As prescribed in paragraph 9a, FM 21-6 except D (5); 
T of Opus (10); Island Cs (10); Base Cs (10); Def Cs 
(10); B (5); R (10); Bn (5) except Bn 1 (10); C (10). 
For explanation of symbols, see FM 21-6. 
24 
AGO 311D 
U. S. GOVERNMENT PRINTING OFFICE: 1944 FM 21-40 
*C 5 
BASIC FIELD MANUAL 
DEFENSE AGAINST CHEMICAL ATTACK 
Changes 
No. 5 
WAR DEPARTMENT 
Washington 25, D. C., 1 May 1945 
FM 21-40, 7 September 1942, is changed as follows: 
7.6. Description of Screening Smokes (As added by C 4). 
Thysical state 
Miscellaneous 
, * * 
* ♦ ♦ 
Hexachlorethane Mixture (HC) 
• 
Solid; produces dense white smoke when 
burned. 
• » * 
Used in smoke pots: high obscuring 
power. 
* ♦ • 
9.2. Blister Gases (As added by C 4).—a. General. 
b. First-aid procedure. 
(3) Liquid burns demand 
♦These changes supersede section IV, Circular No. 237, War Department, 
1944; section I, Circular No. 325, War Department, 1943; and section VI, 
Circular No. 95, War Department, 1943. 
the following chart: 
AGO 16D—May 6372048—45 Area 
affected 
Mustard gas and nitrogen mustards 
Lewisite and otherarsemcak (Ethyl- 
dichlorarsine, Methyldichlorar- 
sine, and Phenyldichlorarsine) 
effecls 
Physiological effects 
First aid (Superseded) 
a. Procedure: Immediately after the eye has been contaminated by a 
liquid blister gas, do the following: 
(1) Squeeze BAL eye ointment directly into the lower part of the eye 
and massage the eye for 1 minute. 
(2) Irrigate the eye with water from a canteen or other available un- 
contaminated source, pouring the water directly and slowly into the eye 
for at least 30 seconds, or until the canteen is empty; but not for longer than 
2 minutes. If BAL eye ointment is not immediately available, the eye 
should be irrigated as early as possible without waiting to obtain the 
ointment. 
b. Discussion: The treatment must be completed before the gas mask 
is put on, in spite of the presence of vapor Therefore, the individual 
E 
should hold his breath as much as possible. BAL eye ointment placed 
in an uncontaminated eye is quite irritating and causes immediate sting 
ing and blinking which may interfere with the individual's combat 
T 
ability for a period up to 15 minutes. Therefore, BAL eye ointment 
should be used in the eye only when the individual is fairly certain that 
his eye has been contaminated by liquid blister gas. The chance of 
E 
liquid contamination is slight except when in close vicinity of a shell or 
bomb burst or in a direct airplane spray. Liquid mustard in the eye 
causes no immediate pain or discomfort. When BAL eye ointment is 
S 
placed into an eye contaminated with liquid mustard there will be imme- 
diate irritation and blinking. This 
is to be expected and treatment should 
not be discontinued because of it. The irritation from the ointment stops 
as soon as the irrigation with water is begun. However, the irrigation 
should not be stopped as soon as the stinging disappears, but should be 
continued for the length of time outlined earlier in this paragraph. When 
liquid lewisite is the contaminating agent, the immediate pain and blink- 
ing caused by the agent is rapidly relieved by the use of B A L eye ointment. 
The blinking may be so uncontrolled as to preclude the immediate place- 
ment of ointment into the lower part of the eye. In such cases the oint- 
ment may be put on the outer lids and massaged well, thus working some 
of the ointment between the lids into the eye. This will relieve the pain 
and blinking to such an extent as to permit the direct placement of the 
ointment into the lower part of the eye. In contaminations by liquid 
mustard, the initiation of treatment within the first few seconds is mark- 
edly effective, but after 2 minutes is of very little value. In the case of 
lewisite contamination, BAL eye ointment is effective for a longer period 
of time. If it is used within 1 minute after the contamination, the eye 
usually recovers in a few days. 
■ 34.1. Voice Transmission Properties of Gas Masks. 
(Added.)—a. Combat service mask of lightweight service mask 
can be worn without impairing accuracy of voice transmission 
over field radios and telephones. Volume of reception, however, 
is reduced when sender is wearing a gas mask. Satisfactory 
transmission results if the following precautions are observed 
by the wearer: 
(1) Hold radio transmitter in direct contact with outlet 
valve unless blurring results, in which case, hold transmitter 
2 
AGO 16D about 3 inches away from and directly in front of outlet valve. 
(2) Hold telephone transmitter in direct contact with outlet 
valve unless blurring results, in which case, hold transmitter 
above and to the left of outlet valve against lower part of left 
eyepiece. 
I). Service gas mask or diaphragm mask, when worn, affects 
the audibility of telephone or radio conversations. This is 
partially overcome by holding transmitter of radio or telephone 
directly in front of and close to diaphragm of diaphragm mask, 
or outlet valve of service mask, while talking. Holding trans- 
mitter in this position may cause receiver to be moved from the 
ear. Consequently, the person at the other end of the line 
must be prevented from talking when he cannot be heard by the 
person wearing the mask. The person not wearing a mask 
should be informed that a gas mask is being worn by the other 
party and that the word “over” will be used each time he has 
finished talking to indicate that he is prepared to listen. 
■ 47. Gas Officers, Ground and Service Forces.—a. Each regi- 
ment and battalion will have at all times a minimum of one 
unit gas officer and one gas noncommissioned officer who are 
qualified instructors, and each company, including separate 
companies, will have a minimum of one unit gas officer and 
two gas noncommissioned officers. These officers and * * * 
officer will overlap. 
d. Following is a list of the mox‘e important duties of regi- 
mental. battalion, and company gas officers: 
(1) General duties. 
(g) (Superseded.) Supervision of the training of a squad per 
company in decontamination methods. 
■ 49. Post Chemical Officer.—a. The post chemical * * * 
ammunition are concerned. Commanders of nondivisional 
units and commands (including replacement training centers) 
in which a unit or staff chemical officer is not available may 
request and receive the assistance of post chemical officers 
in the training of their units or commands in defense against 
chemical attack. Tactical units, such * * * this tactical 
unit. 
AGO 16V 
3 f. Rescinded. 
■ 85. Inspection Procedures.—a. General.—Each individual is 
* * * should be corrected. Inspections should be made not 
only for faulty equipment but also as a check on training 
efficiency and gas discipline of personnel. Before going into 
* * * the unit commander. 
h. Inspection of hose connections. (Added.) Gas masks 
equipped with hose tubes should be inspected weekly, when in 
service, to ascertain that the hose tube connections at the face- 
pieces and canisters are firm and gastight. Inspections should 
be made under direct supervision of the company commander. 
Examination of synthetic rubber hose tube connections should 
be especially thorough. Tests should be performed by vigorous 
hand twisting of the connections, followed by hand pulling, don- 
ning facepiece, inhaling to collapse facepiece for a period of 10 
seconds, and noting that leakage is absent. No leakage should 
be permitted. If leakage is found at hose tube connections, 
leaking masks should be rehabilitated by renewing wire bindings, 
as provided in TM 3-205. Similar tests should be made when 
each mask is newly issued. 
■ 106. Fitting. Instruction in proper fitting, slinging, and 
adjustment of gas masks is a command responsibility. Com- 
manding officers should take such measures as are necessary 
to insure adequate instruction in the correct fitting, sling, 
and adjustment of the mask fox all individuals within their 
commands. This responsibility cannot be delegated to non- 
commissioned officers. Therefore, when gas masks are is- 
sued it is necessary that; (1) each individual be properly 
fitted as to face size; (2) provision be made for the necessary 
training in the correct methods of slinging the mask in its 
various positions, including removing and replacing the mask 
in the carrier (C 1) and the proper use of the pockets of 
the cai’rier; and (3) instructions are given in the adjustment 
of the mask. (See C 1.) 
a. Facepiece. (Superseded.) Facepieces must lit wearer to 
secure a comfortable, gastight seal. Slight dimensional varia- 
tions may occur among facepiece molds of one manufacturer, 
or among the molds of different manufacturers. These varia- 
tions may mean the difference between a comfortable gastight 
fit and an improper, uncomfortable lit. Due to variations in 
manufacturing processes, the universal facepiece comes in three 
4 
AGO 16D sizes: SU (small universal), U (universal), LU (large uni- 
versal). The universal size, with the variations SU and LU, 
affords a good serviceable fit and ample protection in approxi- 
mately 95 percent of the cases. Faces which are too large to 
be satisfactorily fitted with the universal size (U) should be 
fitted with an L or LU size; faces which are too small should 
be fitted with an S or SU size. No effort should be made to 
make the universal size (U) fit by making straps too tight. 
Note.—Some gas mask facepieces (diaphragm, universal service, and 
small size service) marked “Acushnet” or “APC” have been found to 
exert temple pressure and cannot be worn comfortably by some person- 
nel. The same condition may, however, be observed with facepieces 
with other markings. Any facepiece which does not fit properly should 
be disinfected for subsequent issue and other facepieces tried on until a 
good fit is obtained. Facepieces with markings as described below have 
been found to exert temple pressure and cannot be worn comfortably by 
some personnel. 
(1) Lozenge type marking. Reading from top to bottom: 
Lot ; “Acushnet” in script, surrounded by an ellipse; 
M ; an(j a date marking of 4-42 or higher. 
(2) Medallion type marking. Consists of two or three con- 
centric circles. In the inner circle, reading from top to bottom, 
are: 43/APC/M . From 1 to 28 dots are included between 
the outer circles. 
(3) Combination marking. Consists of a modified lozenge 
type marking with the word “Acushnet” in script on one side 
of the outer chin section, and on the opposite section, dots on 
the periphery of a circle surrounding the numeral 43. 
b. Fitting. 
■ 106.1 Nosecup. (Added.)—a. General.—Facepiece of the 
lightweight service mask is equipped with a rubber nosecup 
(fig. 90.1) which prevents exhaled air from coming in contact 
with the lenses, thus lessening the tendency of the lens to fog 
or frost. (See TM 3-205.) 
b. Adjustment.—It may be found that the nosecup presses on 
the bridge of the nose causing discomfort. Substitution of an- 
other mask with faceblank made by a different manufacturer 
may overcome this condition. If substitution does not solve 
the difficulty, nosecup may be altered under supervision of a 
gas officer. Rubber material of nosecup is trimmed away, or 
slit where it rests on bridge of nose. Before making a slit in 
the nosecup, reinforce it by cementing a piece of patching fabric 
from the company gas mask repair kit Mil in such a position 
AGO 1GD 
5 that the slit can be made in the area thus reinforced. This 
prevents further tearing. 
Figure 90.1 (Added.)—Gas mask facepiece showing nosecup. 
■ 107. Gas Chamber Test for Fitting. 
c. Gas chamber exercise. 
(1) Phase I.— (a) Fill the gas * * * gas (chloracetophe- 
none, CN). For every 1,000 cubic feet of space in the chamber 
6 
AGO 16D use one CN capsule. (Place the capsule * * ♦ mask is afford- 
ing. 
■ 110. Rules for Care and Use. 
d. Disposition ivhile traveling. (Added.)—Gas masks should 
be carried on person, not packed in baggage, while traveling. 
Packing of gas masks in barracks bags may result in broken 
eyepieces, crushed canisters, and torn carriers. 
e. Protection against extreme cold. (Added.) In extreme 
cold, gas mask facepieces become stiff. This stiffness disappears 
when the facepiece is placed in a warm room or when facepiece 
is carried under the clothing when wearer is out of doors. The 
facepiece may also be softened by kneading it with the hands. A 
more satisfactory method, where practicable, is to store the mask 
in a warn! room, before issue. 
1! 111. Storage in Organizations.—a. The following rules 
* * * storage of masks: 
(1) Store in a dry place, avoiding extremes of temperature. 
■ 114. Use.—Protective clothing (par. 35a) * * * likely be 
encountered. In the second situation, permeable protective 
(impregnated) clothing (two layers) provides good protection 
for all cases where blister gas vapor or spray is encountered. 
6. Permeable clothing.—The permeable type * * * and 
small drops. Increasing the amount of impregnite above the 
minimum does not correspondingly increase protection against 
larger drops. The ordinary field * * * also be worn. 
■ 127. Detection Devices. 
b. Paper, liquid vesicant detector, M6.—This item consists 
* * * gas detector paint. Either DANG, M4 ointment, or 
M5 ointment, applied to detector paper, causes an immediate 
color change similar to that produced by liquid vesicants. 
The paper may be used to detect liquid vesicants in— 
■ 132. For Mustard Gas. 
b. Chlorinated lime (bleaching ponder).— (1) This material 
is * * * for chlorinated lime. 
AGO 16D 
7 (2) (Superseded.) An alternative method of using chlorin- 
ated lime is to mix it with water to form slurry. This is a 
50-50 mixture by weight of bleaching powder and water. 
Slurry is spread over the surface to be decontaminated and left 
for 24 hours if possible. The 50 50 slurry mixture is the most 
effective mixture for use with brooms or swabs. If mixed by 
volume rather than by weight, 6 shovelfuls of bleach are used 
with one 14-quart bucketful of water. Complete coverage is 
necessary and should be followed by scrubbing to dislodge blister 
gas and till cracks with slurry. Slurry should remain in contact 
with the contaminated surface for from 6 to 24 hours, after which 
it is removed by washing down, scrubbing, and rinsing with 
water. 
(3) (Superseded.) (As added by C 1.) Another method 
of using chlorinated lime is in the 400-gallon power-driven de- 
contaminating apparatus. (See par. 138.) 
d. Miscellaneous chemicals. 
(3) Neutralising agents.—Alkalies such as * * * action 
of water. A solution of 3 pounds of soap shavings or soap 
powder and 3 pounds of washing soda per 100 gallons of 
water provides a good detergent for spraying. Semisolid 
and liquid commercial detergents are also suitable. 
■ 138. Poweb-Dkiven Decontaminating Apparatus.—a. Gen- 
eral. 
b. Charging. (Superseded.) (1) Mixture. Forty parts by 
weight of bleach and 60 parts by weight of water are agitated 
in tank for from 4 to 20 minutes, depending upon the charge. 
An apparatus accommodates a mixture of 1,300 pounds of bleach 
and 224 gallons of water, and requires up to 45 minutes to load 
and mix. Personnel should wear masks when emptying con- 
tainers of bleach. 
(2) Antiset agent. If available, add antiset (sugar) in the 
proportion of % pound of antiset per 100 pounds of bleach. 
Antiset must be added to the water before the bleach is added. 
Antiset agent helps prevent clogging of bleach in the apparatus. 
■ 139. Bathing Units. (Superseded.) Men who have been 
contaminated with chemical agents should bathe with warm 
8 
AGO 16D water as prescribed in paragraph 116&. The M3A2 400-gallon 
power-driven decontaminating apparatus and Ml portable water 
heater, which is auxiliary equipment issued with the 400-gallon 
apparatus, provide field bathing facilities. (See TM 3-223 and 
TM 3-228.) 
■ 147. Materials. 
e. Rubber and leather.—Rubber and leather * * * in warm 
water. Heavily contaminated rubber may be decontaminated 
by submerging it completely for a sufficient time in plain 
water maintained just below the boiling pont. Two hours 
suffice for gloves, 3 hours for other items. If contamina- 
tion is light or caused by vapor, the materials may be aired 
in the sun or wind for several days. DANC should not be 
used to decontaminate rubber, except rugged items such as 
gloves. Leather may be decontaminated satisfactorily if 
immersed in water of from 122° to 131° Fahrenheit for 4 
to 6 hours, allowed to dry in air (no excess heat applied), 
and subsequently treated with shoe impregnite Ml. DANC 
is suitable for use on leather. (See TM 3—220.) 
■ 177.1. Combat Efficiency. (Added.) Emphasis should be 
given to wearing the gas mask in training exercises. It pre- 
vents serious reduction in combat efficiency of troops who may 
have to wear the mask for long periods during a gas attack. 
Wearing the mask should not be confined to gas mask drill. 
Suggested activities during which troops could wear the mask 
at least part of the time include: day and night marches; field 
and firing exercises; at double time for short distances; per- 
forming regular duties; and participation in athletic events such 
as baseball, softball, and volley ball. A definite amount of time 
each week devoted to such training insures combat efficiency of 
troops during a gas attack. 
■ 187. Charts. (Superseded.) Colored charts supported by a 
steel frame have been prepared by the Chemical Warfare Service. 
Five drawings in the set, considered suitable for continued use in 
training, are— 
Gas mask canister. 
Typical arrangement for gasproofing clugouts. 
4.2- chemical mortar shell. 
4.2- chemical mortar. 
HO smoke pot. 
AGO 101) 
9 Other drawings of the set are obsolete and should not be used 
in training. 
[AG 300.7 (5 Mar 45)] 
By obdek of the Secretary of War : 
Official : 
J. A. ULIO 
Major General 
The Adjutant General 
G. C. MARSHALL 
Chief of Staff 
Distribution : 
AAF (10) ; AGF (40) ; ASF (2) ; T of Opns (10) ; AAF 
Comds (5) ; Arm & Sv Bd (2) ; Def Comd (10) ; S Div 
ASF (1) ; Tech Sv (10) ; SvC (10) ; PE (4) ; Sub PE 
(4) ; Stg A (2) ; PG (2) ; Ars 3 (4) ; Dep (1) except ASF 
Dep (4) ; Pro Dist 3 (2) ; GII (2) ; Sell (1) except Gen 
& Sp Sv Sch (10) ; USMA (20) ; Tng C (5) ; A (10) ; 
CHQ (10) ; D (5) ; B (3) ; R (5) ; Bn (5) ; O (5) ; AF 
(5) ; W (2) ; G (2) ; S (2) ; F (1). 
Refer to FM 21-6 for explanation of distribution formula. 
10 
AGO 16D 
U. S. GOVERNMENT PRINTING 0FFICE:1945