PUBLIC HEALTH BULLETIN 
No. 269 
THE HEALTH OF WORKERS 
IN DUSTY TRADES 
YU. Restudy of a Group of Granite Workers 
Federal Security Agency 
U. S. PUBLIC HEALTH SERVICE 
WASHINGTON, D. C. Federal Security Agency 
U. S. PUBLIC HEALTH SERVICE 
Public Health Bulletin No. 269 
THE HEALTH OF 
WORKERS IN DUSTY TRADES 
VII. Restudy of a Group of Granite Workers 
By 
ALBERT E. RUSSELL, Senior Surgeon 
From the Division of Industrial Hygiene 
National Institute of Health 
PREPARED BY DIRECTION OF THE SURGEON GENERAL 
UNITED STATES 
GOVERNMENT PRINTING OFFICE 
WASHINGTON : 1941 
For sale by the Superintendent of Documents, Washington, D. C. - -- -- -- - Price 15 cents ORGANIZATION OF THE NATIONAL INSTITUTE OF HEALTH 
Thomas P arran, Surgeon General, United States Public Health Service 
L. R. Thompson, Director, National Institute of Health 
Division of Biologies Control.—Chief, Senior Surgeon M. V. Veldee. 
Division of Chemistry.—Chief, Professor C. S. Hudson. 
Division of Chemotherapy.—Chief, Surgeon W. H. Sebrell, Jr. 
Division of Industrial Hygiene.—Chief, Medical Director J. G. Townsend. 
Division of Infectious Diseases.—Chief, Senior Surgeon R. E. Dyer. 
Division of Pathology.—Chief, Senior Surgeon R. D. Lillie. 
Division of Public Health Methods.—Chief, G. St. J. Perrott. 
Division of Zoology.—-Chief, Professor Willard H. Wright. 
National Cancer Institute.—Chief, Pharmacologist Director Carl Voegtlin 
Ill FOREWORD 
The progress of silicosis is a subject of great interest to industrial- 
ists, to industrial hygienists, and to jurists. Opportunities to make 
extensive studies of the condition have been rather limited, but 
observations made on a group of granite workers in Vermont in 1924-26 
and again in 1937-38 make possible a rather detailed inquiry into the 
progress of this condition. 
In 1924 the Public Health Service undertook the study of the health 
of workers in dusty trades. Investigation of the effects of exposure 
to siliceous dust was under the direct charge of the author of the 
present report. The findings of the earlier study were published as 
Public Health Bulletin No. 187, The Health of Workers in Dusty 
Trades. 11. Exposure to Siliceous Dust (Granite Industry). 
In 1937-38 the same workers were reexamined. The results of 
this second study are the subject of the present report. X-ray 
photographs available from the earlier survey are presented together 
with photographs made in 1937-38 for the purpose of illustrating the 
changes which have occurred during the interim. In linking the two 
studies it has been necessary to review briefly the original study as it 
relates to working conditions, physical examinations, and morbidity. 
New material herein presented discloses the effect of exposure to 
granite dust of known concentration and silica content. The original 
study was followed up after a lapse of from 12 to 14 years. The 
different results due to this same dust in varying concentrations are 
shown, and form the basis for recommendations for control measures. 
This is one of the most important points brought out in this report. 
It has been demonstrated in this present study, that in the same indus- 
try there were differences in reaction to the dust hazard in direct 
proportion to the intensity of dustiness. This finding emphasizes 
the futility of trying to evaluate the extent of dust hazards without 
dust counting. 
Confusion has arisen in the past when the results of one study of 
dust exposure have been compared with another where the concen- 
tration and the silica content varied. Most notable in this regard are 
the early attempts to classify silicosis in the United States according 
to the standards in South Africa where the silica content of the dust 
is very high and the workers and their living conditions are quite 
different from those in the United States. 
:vi VI 
The diagnoses of tuberculosis in cases presented herein were made 
on the basis of physical examinations and laboratory reports rather 
than the X-ray alone. 
The present report deals primarily with the reexamination of as 
many as possible of the identical workers who were examined in the 
1924-26 study. There were 642 granite workers examined during 
that period. There have been more than 150 known deaths in this 
original group since the close of the original study (October 1926). 
Fifty-eight of the original workers studied refused to return for reex- 
amination. Some of the workers who were examined in the original 
study had moved away and information concerning their status and 
the condition of their health was not obtainable. There remained 116 
workers on whom examinations had been made both in the original 
study and in the restudy in 1937-38. CONTENTS 
Page 
Foreword v 
Resume of the 1924-26 study of granite workers 1 
Chemistry and concentration of dust 2 
Description of the Vermont granite workers 2 
Sickness and mortality records 3 
General comments on silicosis and tuberculosis among granite w'orkers. 7 
Clinical and X-ray characteristics of silicosis and tuberculosis in granite 
workers 8 
Clinical findings 8 
Physical examinations 9 
X-ray findings 9 
Comparison of findings on persons examined in 1924-26 and again in 
1937-38 11 
Granite cutters, groups A and B, who continued at occupation 13 
Granite cutters, groups A and B, who changed to nondusty occupations. 44 
Low dust exposure groups C and D 55 
Statistical summary 62 
General statement and recommendations 66 
Extent of dust exposure in the past 66 
Practical limits of dustiness 66 
The ventilation problem. 67 
Medical supervision 69 
Permissible concentrations for the particular industries in the localities 
indicated—-table 7 71 
;vn THE HEALTH OF WORKERS IN DUSTY TRADES 
VII. RESTUDY OF A GROUP OF 
GRANITE WORKERS 
RESUME OF THE 1924 26 STUDY OF GRANITE WORKERS 
The Public Health Service began a series of studies in 1924 dealing 
with the health of workers in dusty trades. The method of approach 
in each of these studies was the same insofar as this was possible. 
The procedure employed was largely as follows; 
1. Study of absenteeism—its causes, 
2. Physical examinations, X-rays, laboratory examinations, 
autopsies, etc. 
3. Statistical analysis of mortality data—local and general, 
where applicable. 
4. Study of environment of workers—industrial processes, 
dustiness, chemical and petrographic analyses of dust. 
5. Study of remedial measures—ventilation, effect of change of 
processes, effect of protective equipment, and efficiency of 
protective equipment. 
Studies were reported in the following bulletins under the general 
title, The Health of Workers in Dusty Trades: 
I. Health of Workers in a Portland Cement Plant, Public Health 
Bulletin No. 176. )?- 
11. Exposure to Siliceous Dust (Granite Industry), Public Health 
Bulletin No. 187. J?. 
111. Exposure to Dust in Coal Mining, Public Health Bulletin No. 
208. ) 
IV. Exposure to Dust in a Textile Plant, Public Health Bulletin 
No. 208. / 
V. Exposure to Dust in a Silverware Manufacturing Plant, Public 
Health Bulletin No. 208. 
VI. Exposure to Municipal Dust (Street Cleaners in New York 
City), Public Health Bulletin No. 208. 
In the first report a discussion set forth in some detail opinions of 
authorities as to the nature of pneumoconiosis caused by the different 
kinds of dust, although a review of all of the literature available on the 
subject at that time was not attempted. 
328256—41 2 2 
A general summary and statement of findings was given in Bulletin 
No. 208. 
Prior to 1924, when these studies were begun, knowledge of the 
effects of industrial dust hazards on the health of workers had been 
gained largely from a study of occupational mortality statistics or from 
physical examinations of sample groups of employees in various in- 
dustries. The exception to this was the study by Dr. A. J. Lanza 
of the Public Health Service of 433 cases of miners’ consumption 
among zinc miners in southwestern Missouri; a report of the findings 
was published in 1917, in Public Health Bulletin No. 85. 
CHEMISTRY AND CONCENTRATION OF DUST 
It was shown by petrographic analysis that granite dust in Barre, 
Vt., contained 30 to 35 percent of crystalline silica or quartz. Con- 
centration and size of dust particles are a part of the etiology of silicosis 
and rank in equal importance with the chemistry of the dust. It is 
necessary to know the concentration of a dust before a definite decision 
can be made whether such dust is harmless. A toxic dust in a low 
concentration may not produce a disabling silicosis, but when the 
threshold of tolerance is passed, the disease will develop at a rate 
proportionate to the concentration and to the percentage of free silica 
present. This was exemplified in the study of the various dust count 
groups of the granite industry. 
Two hundred and twenty dust determinations were made on the 
various occupations in the industry. The concentration ranged from 
an average of 60 million particles per cubic foot for the workers using 
hand-pneumatic tools, down to 2 million particles per cubic foot for 
the office workers. The average exposure for the operators of surface 
cutting machines was 44 million particles; for carvers and letterers, 
37 million particles; and for tool grinders, 27 million particles. The 
dust to which the tool grinders were exposed was wet. The average 
plant dustiness was about 20 million particles per cubic foot. 
For the purpose of determining the effect of exposure to dust, the 
occupations were classified in four groups on the basis of these dust 
counts, as follows; Group A, hand pneumatic-tool cutters; group B. 
surface machine operators and cutters exposed to more than the 
average dustiness of the plants; group C, occupations in which the 
workers were exposed to the average dustiness of the plants (lumpers, 
bed setters, etc.); group D, occupations in which the workers were 
exposed to less than the average dustiness of the plants. 
DESCRIPTION OF THE VERMONT GRANITE WORKERS 
The granite cutters, on the whole, were of good physique; average 
height 66.9 inches, weight 157 lbs. They usually remained in the 3 
industry all of their working life. Seventy-five percent of them had 
been employed in the industry for more than 10 years. Their wages 
were good and their living conditions were much above the average 
for industrial workers. 
The minimum wage for granite cutters was $1 an hour, or $8 a day. 
Carvers, sandblasters, and other highly skilled workers received more. 
The polishers, cranemen, lumpers, and other less skilled workers 
received $0.77 per hour. Incidentally, this group had a lower tuber- 
culosis rate than the cutters, who received better wages. The work- 
ing hours during the time of our observations were 8 hours a day, with 
a half day on Saturday. 
Eighty-three percent of the workers in the granite industry com- 
prised five racial groups: Italian (northern), Scotch, American, Span- 
ish, and French-Canadian. The Italians who made up 33 percent of 
the group are from the northern provinces of Italy; many are from 
the Swiss border. The Scotch are principally from Aberdeen. The 
Americans are largely local New Englanders, and the Spanish are 
from the Province of Santander. (The racial groups have not 
changed materially since the original study.) 
SICKNESS AND MORTALITY RECORDS 
The relation between the general sickness records and the dustiness 
of each occupation is of particular significance. The incidence of 
illness from all causes (disabling for 8 days or longer) in groups A 
and B combined was about 215 per 1,000 years of observation: in 
group C, it was 105: and in group Dit was 61. All respiratory ill- 
nesses showed a striking difference. When the sickness due to tuber- 
culosis was eliminated from the total, the respiratory illness rates 
were still higher in groups A and B than in C and D, due primarily to 
influenza and colds. It seems obvious that the excessive dust hazard 
is reflected in the general sickness rates as well as in the prevalence 
of tuberculosis. Groups C and D seemed to have moderate rates. 
The rapid rise with length of service in the sickness rate among 
workers in groups A and B is brought out in figure 1. 
The incidence of silicosis and tuberculosis did not seem to vary sig- 
nificantly according to race. The sickness records showed that dis- 
ability from pulmonary conditions, experienced by these workers, 
varied in proportion to the length of service and extent of dust con- 
centration. 
The rate of sickness for all causes among those who subsequently 
developed tuberculosis was nearly three times as high as it was among 
those who did not develop the disease. 
The percentage of cases of tuberculosis in the various dust-count 
groups is shown in figure 2. The contrast between the A-B groups 4 
and the C-D groups is extremely significant. Group D furnished no 
cases and group C but three cases. The rise in incidence of the disease 
in group A-B with length of service is so unmistakable and so rapid 
INCIDENCE RATE PER 1,000 YEARS OF OBSERVATION 
20 MILLION OR LESS DUST PARTICLES PER CUBIC FOOT 
0 10 20 30 40 
YEARS IN GRANITE INDUSTRY 
1 Mean for all lengths of service. The data are too small to establish a reliable trend. 
Figure I.—lncidence of Sickness from All Causes by Length of Service 
and Dust Count Groups. 
that there can be no question but that it is associated with the dust 
hazard of the industry. 
Figure 3 shows the increase in deaths from tuberculosis since the 
introduction of pneumatic tools. The rates for granite cutters are 
compared to those of males in rural Vermont and in the registration 5 
area of the United States as of 1925. The differences point definitely 
to the dust hazard incident to the new method of cutting granite. 
The annual tuberculosis death rate per thousand for dust count 
group A was found to be 19.5, and for group B, 12.8. In groups C 
PERCENTAGE 
YEARS IN GRANITE INDUSTRY 
Figure 2.—Percentage of Workers Diagnosed on Physical Examination 
as Having Tuberculosis (Active). 
and D only 1 death occurred (a rate of 1.2 per 1,000). When the two 
groups with the highest dust exposure are considered together, the 
death rate from tuberculosis per thousand was 26 for 20 to 24 years’ 
exposure, 29 for 25 to 34 years’ exposure and 47 for longer periods. 
Although the mortality rates were found to be high, a word of 
warning was given in Public Health Bulletin 187 that even higher 6 
rates should be expected. The present condition has developed since 
the introduction of hand-pneumatic tools for cutting granite. This 
change from the hand mallet and chisel began about 1894, hence the 
effect of the increased and intensive exposure to dust may not yet 
have been fully experienced. The lessening of the dust hazard by 
improved ventilation and local exhaust will eventually bring about a 
reduction in the death rate from tuberculosis. 
ANNUAL DEATH RATE PER 1,000 PERSONS EMPLOYED 
YEAR 
Figure 3.—lncrease in Mortality From Pulmonary Tuberculosis Since 
Introduction of Pneumatic Tools in Granite Cutting. 
Since the introduction of pneumatic tools, the mortality among 
granite cutters has been rising year by year. (See fig. 3.) 2 
2 Data for the period since the original Public Health Service study are summarized in the following table 
Data on mortality for Vermont, Washington County, and Barre City per thousand population, 1926-36 
Death rates 
Vermont 
Vermont 
except 
Washing- 
ton County 
Washing- 
ton 
County 
Washing- 
ton County 
except 
Barre City 
Barre 
City 
Barre gran- 
ite plant 
workers 
Death rate from all causes; 
192(5-30 _ 
14.3 
14.0 
16.7 
16.8 
16.4 
15.8 
1931-35 
13. 6 
13.5 
14.8 
14.8 
14.7 
23.5 
Death rate from tuberculosis: 
1926-30 
.61 
.41 
2.28 
1.74 
3.81 
10.6 
1931-35 
.48 
.30 
1.84 
1.31 
3. 24 
16.8 
Percentage of deaths due to 
tuberculosis: 
1926-30 
4.3 
2.9 
13.6 
10.4 
23.2 
66. (5 
1931-35 
3. 5 
2.2 
12.5 
8.8 
22.0 
71.5 
Population: 
1920 census- 
352,428 
313, 507 
38, 921 
28,913 
10,008 
1 2, 500 
1930 census 
351,061 
309, 789 
41,272 
29,967 
11,305 
i 2,000 
INo actual figures available. Estimates based upon arbitrary figures. A survey in 1937 showed 
Barre City granite plant workers to number 1,533. 7 
GENERAL COMMENTS ON SILICOSIS AND TUBERCULOSIS AMONG 
GRANITE WORKERS 
The most important conclusion of the study has been a confirmation 
of the findings in the original study which pictured the results of ex- 
posure for many years to a dust of a known character. The significant 
features of the picture are: 
(a) The long period of service before the liability to tuberculosis 
becomes manifest (generally about 20 years or more). 
(b) The sharp correlation between the length of exposure to the dust 
and the prevalence of tuberculosis and also the death rate from this 
disease. 
(c) The close relation between extent of dust exposure and the 
health of the workers. 
(d) The universal occurrence of silicosis among workers in groups 
A and B. 
(e) The large proportion of workers finally succumbing to tuber- 
culosis. 
(/) The invariably fatal form of the disease (tuberculosis) usually 
in a comparatively short time after it becomes a clinical entity. 
(g) The different character of silicosis as manifested by the X-rays 
compared to that shown where there is exposure to a dust of a much 
higher content of free silica. 
(h) The location of the initial tuberculous lesion, usually basal 
or in the middle portions, where the disease complicates silicosis. 
This is in contrast to the usual location of the lesions in uncomplicated 
tuberculosis. 
(i) The absence of deaths from silicosis per se, tuberculosis almost 
invariably intervening. 
(j) The failure of workers to recover from silicosis upon going into 
nondusty trades. 
(k) The high incidence of sickness of a severe nature from causes 
other than tuberculosis. 
(l) The rising sickness and mortality rates from tuberculosis due to 
the longer use of the pneumatic tools. 
(m) The appallingly high death rates at the present time due to 
tuberculosis, compared with normal industrial experience. CLINICAL AND X-RAY CHARACTERISTICS OF SILICOSIS AND 
TUBERCULOSIS IN GRANITE WORKERS 
CLINICAL FINDINGS 
It should be borne in mind that silicosis occurs in uncomplicated form 
as a simple silicosis and also with infection which is almost invariably 
tuberculous. The physical and clinical aspects of these two condi- 
tions are quite different in each instance. Since silicosis and tuber- 
culosis may frequently co-exist, clinical considerations are important 
in diagnosis and prognosis. The general considerations briefly 
presented here are based on the experience of both the 1924-20 and 
1937-38 studies. Uncomplicated silicosis is not accompanied by a 
general toxemia, which is in contrast to the findings when active 
tuberculosis is present. The patient with simple silicosis may be 
able to continue his work and usual routine without much inconven- 
ience. He is usually found to be well nourished and apparently 
healthy until he is in the advanced stage of the disease. 
Pathogenesis.—The dust enters the lungs in a downward direction 
and reaches the lower and middle portions before it becomes arrested 
on the moist walls of the bronchi and bronchioles. It has been stated 
that very little dust reaches the apical portions. The right bronchus 
is larger than the left and enters the lung at about a 24° angle, whereas 
the left, the smaller one, enters at an angle of about 45°, and the dust 
is more readily impinged against moist walls of the pulmonary struc- 
tures before it reaches the bronchioles. It can be readily seen that 
there is a good reason for more pathologic changes in the right lung. 
Incidentally, there were more early tuberculous lesions found in (lie 
right lung than in the left. 
As the condition advanced, there occurred more dense shadows due 
to the coalescence of the silicotic nodules and the increasing density of 
the fibrosis. There were evidences of irregularities of the contour of 
the diaphragm due to pleural thickening and adhesions. There was 
found dense pleurae in all the cases that came to autopsy. 
The workers in dust count groups A and B, in practically all cases, 
did not show any evidence of silicosis on physical examination until 
after 15 years of dust exposure. Those workers who were exposed to 
less amounts of dust, groups C and D, did not show evidence of the 
disease until after a much longer period of exposure. The diagnosis 
in all these cases was made on history of exposure, physical examina- 9 
tion, and, where possible, by X-ray. In the more advanced cases, 
the symptoms were more evident. 
Dyspnea is usally the first complaint and is quite constant in sili- 
cosis, increasing in severity with length of exposure. In the granite 
workers, the dyspnea continued to increase even after cessation of 
exposure once silicosis was well established. Pains in the chest were a 
common complaint. Granite cutters with uncomplicated silicosis 
usually have a nonproductive cough which seems to cause them no 
inconvenience. They have frequent colds. 
PHYSICAL EXAMINATIONS 
Physical examination will reveal some limitation of chest expansion 
usually in proportion to the extent of exposure. The restriction of 
expansion is symmetrical in contradistinction to the asymmetry found 
in tuberculosis uncomplicated by silicosis. 
Physical examination usually reveals a general impairment of res- 
onance over the chest, the intensity varying with the length of dust 
exposure. This finding is consistent with the character of the gener- 
alized fibrosis of the lungs in silicosis. The fibrosis of tuberculosis is 
localized over the infected area, whereas the fibrosis of silicosis is 
generalized. It may be easy to overlook the presence of impaired 
resonance since it is generalized and there are no local areas to afford 
a contrast in the percussion note as is the case in tuberculosis and 
pneumonia. 
The breath sounds are found to be soft which accentuates the vesic- 
ular type of breathing. Riddell 3 states that “The commonest change 
is in intensity. Breath sounds in silicosis tend to be distant or 
blanketed.” Rales are absent in uncomplicated cases. The intensity 
of signs discovered on physical and X-ray examination are usually 
found to be in direct proportion to the length of dust exposure. 
X-RAY FINDINGS 
When the pathology of uncomplicated silicosis is considered, it can 
be seen that with dust deposited in the lymphatic channels and nodes 
and along the bronchi and in the lulus the pulmonary changes indi- 
cated on the X-ray will be of a generalized nature. The body response 
to silica dust is the formation of fibrous tissue which is indicated on 
the X-ray by lineations which show undulations in their course. 
This characteristic is more prominent as the condition becomes estab- 
lished. There is a predominance of shadows in the lower and middle 
portions of the lungs, with more on the right than the left in uncom- 
plicated cases. As the condition progresses, there is an increase in 
the number and size of the nodulations and later these coalesce and 
3 Riddell, A. R.: Clinical and Radiological Aspects of Silicosis. Canadian Public Health Journal, Feb- 
ruary, 1936, Vol. 27, No. 2. 
328256-41- 3 10 
thereby produce more dense shadows on the X-ray. The process of 
development of fibrosis is indicated by areas of consolidation in the 
more advanced cases. There is usually some evidence of pleural 
changes as indicated by irregularities of the diaphragm and the 
presence of a thickening of the interlobar pleura which usualty appears 
as a line across the field of the right lung. Most of the advanced cases 
presented evidence of pleural changes. 
When active tuberculosis becomes a complication of silicosis in 
granite workers, there are certain changes in symptoms and physical 
findings which usually make it easy to recognize the superimposed 
infection. Workers usually continue at their employment up to this 
time; however, they seem to have minor illnesses and lost time from 
work immediately preceding the onset of clinically active disease. 
These illnesses were reported on the morbidity records as suspected 
pulmonary tuberculosis in many cases, and no doubt were due to 
early manifestations of the superimposed infection. The reasons 
usually given were fatigue, pains in the chest, or the worker would 
say he needed a little rest. These symptoms usually aroused great 
fear on the part of the patient and his family. As the condition pro- 
gressed, there was invariably a history of greatly increased dyspnea, 
increase in cough with the production of sputum, marked fatigue, 
hemoptysis, and in some cases frank hemorrhages. There were 
pains in the chest usually of an acute nature, in some instances so 
severe as to require opiates. 
These patients have a great fear of tuberculosis and usually refrain 
from complaining of symptoms referable to the chest, and in many 
instances it was necessary to obtain the history from members of the 
family. Patients in some instances denied hemoptysis yet members 
of the family reported hemorrhages from the lungs. A history of 
pulmonary hemorrhage was often the earliest manifestation of clinical 
tuberculosis. Other complaints that were elicited in the early cases 
were fever, night sweats, loss of weight and strength, and pains in the 
chest. As the tuberculous infection advanced, there was no great 
difference in the clinical evidence of tuberculosis in these workers and 
that found in the fulminating type of the disease in nonsilicotic per- 
sons. It was usually easy to find tubercle bacilli in the sputum. 
The physical signs of tuberculosis complicating silicosis where a 
general pulmonary fibrosis already exists present variations from those 
which are found in uncomplicated cases. When consolidation and 
cavitation occur, the signs are similar to the usual case of tuberculosis. 
The latent or post tussic rales are constant and not unlike the same 
valuable diagnostic sign in uncomplicated tuberculosis. 
The X-ray characteristics of silicosis and tuberculosis are demon- 
strated in the X-ray reproductions which are presented subsequently, 
especially in the ones from the cases observed in 1937 and 1938. COMPARISON OF FINDINGS ON PERSONS EXAMINED IN 
1924-26 AND AGAIN IN 1937 38 
The granite industry in the United States originally began in 
Vermont and has been carried on there for more than 125 years. The 
workers are men of stable character, substantial citizens, and usually 
remain on the job throughout their lives. The hazard to their health 
because of the nature of their work is of particular interest to physi- 
cians, industrialists, workmen compensation commissioners, and jur- 
ists. The effects of silicosis and its association with tuberculosis are 
of paramount interest. The opportunity for studying the rate of 
progress of silicosis in this country has been rare. It has been hindered 
because of the chronic nature of the condition, its slow development 
and the small number of workers available in a particular locality 
where they might be observed over a period of years. Because of 
excellent relationships which existed between the Public Health 
Service and the workers, manufacturers, unions, physicians, hospitals, 
and State health department in Vermont during the original study, it 
was possible to make supplementary observations of the progress of 
silicosis among the granite workers 
Physicians in South Africa, where gold mining is the principal indus- 
try in which silicosis is a hazard, have been able to follow their cases 
and have contributed most of what we know about the progress of 
silicosis. The type of native workers, their living conditions, and the 
high percentage of silica in the dust are factors which vary greatly 
from that of the granite industry in Vermont. All of the workers in 
granite are white people and have excellent living conditions. 
When these factors are considered it can be seen readily that the 
progress and outcome of the disease would also be different. In- 
cidentally, in the United States there are so many dusty trades in 
which the extent and nature of dust exposure is quite varied that the 
results in one industry are not always comparable to those in another. 
It was not possible to classify the stages of silicosis found among the 
granite workers by the classification which was in use in South Africa 
and largely employed in this country at the time of the publication of 
Bulletin No. 187. The classification of the stages of silicosis in South 
Africa was made as the scientific facts about silicosis were emerging 
and were written into the laws of that country and for that reason 
they have not been changed. The silicosis in granite workers is 
quite different from that which is found in the South African gold 12 
miners as well as from cases in this country with exposure to dust of 
different concentration and silica content. 
The observations on the granite workers were started early in 1937 
and finished in 1938. The objective was to reexamine as many of 
the former workers as possible and to account for those who had died 
or moved away. Excellent cooperation with the State board of health 
and the physicians of Barre was obtained. Offices were established 
at the Barre City Hospital and arrangements were made to use the 
hospital X-ray equipment for making the X-rays. The examinations 
and X-rays were made by the author and Ur. L. E. Judd of the 
division of industrial hygiene of the State board of health, A number 
of granite cutters who were not in the original study were also exam- 
ined; however, they are not included in this report. 
It was possible to make observations on a group of granite workers 
who had continued in their original occupations and whose dust expo- 
sure had remained essentially the same since the period of the original 
Public Health Service study. They had not worked as regularly as 
they did prior to the time of the industrial depression; however, most 
of them had been able to work at intervals. Their exposure to dust 
was lessened somewhat by the smaller amount of work; however, the 
dustiness of their particular occupations remained practically un- 
changed.4 The workers classed according to dust exposure as groups 
A and B in the original study are considered first, and those in groups 
C and D later in the report. 
Brief case histories are presented with the old X-rays. It was not 
possible to get X-rays on all the workers during the first study, and 
many of those who were found to be essentially negative on physical 
examination were not examined by X-ray. Some of these cases are 
presented after the group on whom there are X-rays from both 
studies. 
The progress of silicosis in the cases presented has not been at the 
same rate although the dust exposure has been about the same. 
Study of the cases and their X-rays seems to indicate that the presence 
of infection, which is almost invariably tuberculosis, is the main factor 
in the difference in the rate of development of the condition. In the 
previous study, a number of cases of silicosis apparently without latent 
tuberculous infection were found. This group seems to have had 
slower progress than others with evidence of infection. It should be 
kept in mind that it is not always possible to distinguish between the 
fibrosis of silicosis in the early stages and that of tuberculosis. 
Diagnosis of silicosis should not be made by the X-ray alone. 
However, it is the most valuable procedure in diagnosis and should 
always be employed. X-ray characteristics of silicosis are so pro- 
4 Ventilation in the Granite Industry. Edward C. J. Urban, J. of Ind. Hyg. & Toxicol. 21: 3, (Mar.) 1939 13 
nounced that it may easily become a habit to omit other procedures in 
the diagnosis. The physical examination and history of occupational 
life is also very important and should not be overlooked. Asbestosis, 
mycotic infections, miliary tuberculosis, tuberculous broncho-pneu- 
monia, passive congestion of the lung, and bilateral bronchiectasis are 
conditions which may give X-ray characteristics similar to silicosis. 
Certain metastatic malignant conditions of the lung may give X-ray 
markings suggestive of silicosis. Occasionally X-rays of silicosis will 
show deviations from the usual picture. This emphasizes the impor- 
tance of accounting for the whole occupational life of the worker with 
detailed information relative to occupations which entail dust exposure. 
In the following discussion of the findings on men who were exam- 
ined in 1924-26 and again in 1937-38, a distinction has been made 
between (1) granite cutters (groups A and B) who continued at their 
trades, (2) granite cutters who changed to nondusty occupations, 
and (3) those who were in the low exposure groups (groups C and D) 
at the time of the original study. 
GRANITE CUTTERS, GROUPS A AND B, WHO CONTINUED AT 
OCCUPATION 
A group of cases is presented here to show the progress of silicosis 
that has taken place since the time of the original observations. It has 
been stated that their occupations arc the same as they were during the 
period of original study with the exception that the amount of work to 
which they were accustomed has been less, owing to economic condi- 
tions of the country in the last few years. 
It was possible to observe a few granite cutters in 1931, at which 
time a dust study of quarrymen in Barre was being made. These same 
workers had been observed in the original study. It was also possible 
to obtain a few X-rays of these patients from the Barre City Hospital 
which were made subsequent to 1931; some of these arc presented for 
comparative purposes. 
Nationality, age, and occupation are given in the descriptions with 
each X-ray print. 
Histories are presented briefly with the X-ray prints and very little 
comment seems necessary inasmuch as the progress of the condition is 
quite apparent. The first case illustrated, plates 1, 2, and 3, is inter- 
esting because of the patient’s exemplary habits and strict routine 
of living. He had no complaints at any time during the earlier ob- 
servations except shortness of breath on exertion. In 1937 he com- 
plained of pleurisy pains and a susceptibility to colds. From the 
appearance of the 1937 and 1938 X-rays, it seems that a tuberculous 
complication might intervene at almost any time. 14 
Plate no. 1. 
1925 
CASE 32. J . M . EXAM INED 1 925. SCOTCHMAN. AGE 40. G RAN ITE CUTTER, 
SURFACE MACHINE OPERATOR 21 YEARS. FATHER DIED OF TUBER- 
CULOSIS AT AGE 62; HE WAS ALSO A GRANITE CUTTER. PATIENT 
COMPLAINS OF DYSPNEA; OTHERWISE HE ENJOYS GOOD HEALTH. 
X-RAY SHOWS EARLY SILICOSIS. 15 
PLATE NO. 2 
1931 
CASE 32. J. M. EXAMINED AUGUST 1931. NO COMPLAINTS EXCEPT 
DYSPNEA ON EXERTION. NO EVIDENCE OF CLINICAL TUBERCULOSIS. 16 
Plate No. 3. 
1937 
CASE 32. J. M. EXAMINED APRIL 23, 1937. AGE 52, WEIGHT 145 POUNDS. 
HAS CONTINUED TO CUT GRANITE EXCEPT FOR BRIEF PERIODS SINCE 
PREVIOUS EXAMINATION. COMPLAI NS OF DYSPNEA. ADVANCED SILI- 
COSIS. 17 
The case illustrated in plates 4 and 5, case 99 (A—B group), demon- 
strates that the onset of tuberculosis in this group of silicotic patients 
cannot be easily foretold by the X-ray. The shadows in the right 
hilus of 1925 X-ray seem to indicate a beginning tuberculosis (fourth 
rib near and at periphery, left). This is even more striking in the 
PLATE NO. 4. 
1925 
CASE 99. R. C. EXAMINED JUNE 1, 1925. ITALIAN. AGE 53. HEIGHT 69 
INCHES. WEIGHT 178 POUNDS. G RAN ITE CUTTE R35 YEA RS. MODERATE 
SILICOSIS. 
NOTE (1940).—patient has developed open tuberculosis. 
1937 X-ray. The character of the markings is such that it seems al- 
most certain to be tuberculous; however, it was not possible to demon- 
strate any evidence of it on physical examination. This man has con- 
tinued to work and at present is in good health except for dyspnea. 
328256—41 4 18 
PLATE NO. 5. 
1937 
CASE 99. R. C. EXAMINED MAY 29, 1937. AGE 65. WEIGHT 166 POU N DS. 
HE HAS CONTINUED TO CUT GRANITE SINCE PREVIOUS EXAMINATION 
EXCEPT FOR SHORT INTERVALS. COMPLAINS OF DYSPNEA ON SLIGHT 
EXERTION. CHEST SHOWS EVIDENCE OF ADVANCED SILICOSIS. 19 
Case 186 (A-B group), plates 6 and 7, showed a fine linear type of 
fibrosis in 1925. He has continued at his old occupation since that 
PLATE NO 6. 
1925 
CASE 186. J. S. EXAMINED JANUARY 5, 1925. FINN. AGE 42. HEIGHT 
65 INCHES. WEIGHT 165 POUNDS. GRANITE CUTTER 23 YEARS. MODER- 
ATE SI LICOSIS. X-RAY NO. 45. 
time and in 1937 his X-ray still has some of the linear fibrosis; how- 
ever, there is a tendency to a confluence of the shadows which have 
increased in density since the time of the original X-ray. 20 
PLATE NO. 7. 
1937 
CASE 186. J. S. EXAMINED JUNE 25, 1937. AGE 55, WEIGHT 166 POUNDS. 
HE HAS CONTINUED TO CUT G RAN ITE SI NCE PREVIOUS EX AM I NAT lON . 
ADVANCED SILICOSIS. 21 
Plates 8, 9, and 10, case 11, show only a moderate amount of 
silicosis in the X-rays of 1925 and 1931. The changes indicated in 
the 1937 X-ray are such that it is not possible to make a diagnosis of 
Plate no. 8. 
1925 
CASE 11. J. J. EXAMINED JUNE 11, 1925. HEIGHT 73 I NCHES, WEIGHT 188 
POUNDS. AGE 44. SWEDISH. HAS CUT G RAN ITE 27 YEA RS, 1 3 OF WH ICH 
HAS BEEN IN THE UNITED STATES. WHERE HE USED PNEUMATIC TOOLS. 
CHEST SHOWS EARLY SILICOSIS. X-RAY NO. 106. 
tuberculosis from the X-ray. Physical examination, however, 
showed evidence of rales in the middle portion of the right lung and 
he had evidence of toxemia at that time. The late Professor Kettle 
pointed out that in his opinion the reason why silicotic patients 22 
develop tuberculosis is not because of the damage produced in the 
lymphatic system but because of the presence of silica in the pul- 
monary tissue. This statement seems to carry more weight when 
PLATE NO. 9. 
1931 
CASE 11. J. J. X-RAY WAS MADE IN AUGUST 1931. THERE HAS BEEN AN 
INCREASE IN FIBROSIS BUT NOT TO A MARKED DEGREE. THE HEART 
SHADOW HAS NOT CHANGED APPRECIABLY. HE WAS IN GOOD HEALTH 
AND COMPLAINED OF DYSPNEA ONLY ON EXERTION. 
this case is considered and compared to the one that follows in which 
so much pathologic change is shown in the 1925 X-ray and the unusual 
amount in the 1931 X-ray. There was no evidence of clinical 
tuberculosis in the patient at the time these two X-rays were made. 23 
Plate No. 10. 
1937 
CASE 11. J. J. EXAMINED MARCH 26, 1937. AGE 56, WEIGHT 171 POUNDS. 
FOR THE PAST 5 YEARS HE HAS BEEN WORKING AS A BULL-SET HOLDER 
AND HAS HAD A RELATIVELY LOW AMOUNT OF DUST EXPOSURE. HAS 
NOT WORKED SINCE JANUARY 1937. COMPLAINS OF WEAKNESS, DYSP- 
NEA, AND DEAFNESS. CHEST SHOWS EVIDENCE OF SILICOSIS AND 
TUBERCULOSIS. THERE HAS BEEN A CHANGE IN THE HEART SHADOW 
AND THE DIAPHRAGM. 
NOTE.—PATIENT DIED IN FEBRUARY 1938. 24 
plate no. 11. 
1925 
CASE —. C. G. EXAMINED 1925. FRENCH-CAN ADI AN DESCENT. AGE 48. 
GRANITE CUTTER FOR 29 YEARS, USING A HAND-PNEUMATIC TOOL. 
HEALTH GENERALLY GOOD AND THERE WAS NO MORBIDITY DURING 
THE PERIOD OF OBSERVATION. HEIGHT 68 INCHES, WEIGHT 161 
POUNDS. PHYSICAL EXAMINATION REVEALED EVI DENCE OF ADVANCED 
SILICOSIS. 25 
PLATE NO. 12 
1951 
CASE —. C. G. EXAMINED AUGUST 1931. AGE 54. PATIENT COMPLAINS 
OF EXTREME DYSPNEA. PHYSICAL EXAMINATION REVEALS EVIDENCE 
OF ADVANCED SILICOSIS. NO RALES WERE EVIDENT AND PATIENT HAD 
NO SIGNS OF A TOXEMIA. DYSPNEA WAS SO SEVERE THAT IT WAS 
DISABLI NG. 
NOTE. —PATIENT DIED OF TUBERCULOSIS IN 1931. 
328236—11 5 plate no. 13. 
1925 
CASE 219. J. M. EXAMINED MARCH 12, 1925. SCOTCHMAN. AGE 47. 
HEIGHT 68 INCHES, WEIGHT 142 POUNDS. GRANITE CUTTER (SURFACE 
MACHINE OPERATOR) 22 YEARS. EARLY SILICOSIS. X-RAY NO. 84. 27 
Plate no. 14. 
1937 
CASE 219. J. M. EXAMINED JULY 19, 1937. AGE 59, WEIGHT 129 POUNDS 
HE HAS CONTINUED TO CUT GRANITE SINCE PREVIOUS EXAMINATION. 
ADVANCED SILICOSIS. 28 
Case 87 (A-B group), plates 15 and 16, is remarkable because of 
the nodulation which was evident in the original X-ray. Very few 
of the cases had similar markings and none was as extensive as this 
PLATE NO. 15 
1925 
CASE 87. P. B. EXAMINED DECEMBER 11, 1925. SCOTCHMAN. AGE 52. 
HEIGHT 71 INCHES, WEIGHT 177 POUNDS. G RAN ITE CUTTER. SU RFACE 
MACHINE OPERATOR 32 YEARS. ADVANCED SILICOSIS AND SUSPECTED 
LATENT TUBERCULOSIS. X-RAY NO. 188. GENERAL PHYSICAL CONDI- 
TION IS GOOD. 
one. Examination in 1937 and 1938 did not show any evidence of 
tuberculosis, however, it seemed to be indicated in the X-ray. Com- 
pensatory emphysema is indicated in the 1925 X-ray as well as in 
the 1937 X-ray and the latter shows evidence of a diaphragmatic 
adhesion. 29 
Plate no. 16, 
1937 
CASE 87. P. B. EXAMINED APRIL 26, 1937. AGE 64. HE HAS CONTINUED 
TO CUT STONE EXCEPT FOR BRIEF PERIODSSINCE PREVIOUS EXAMINA- 
TION. WEIGHT 180 POUNDS. COMPLAINS OF DYSPNEA. ADVANCED 
SILICOSIS WITH LATENT INFECTION. 30 
PLATE NO. 17. 
1925 
CASE 55. J. P. EXAM INED FEBRUARY 28, 1925. ITALIAN. AGE3I, HEIGHT 
68 INCHES. WEIGHT 183. G RAN ITE CUTTER 1 3 YEARS. CHEST NEGATIVE. 
X-RAY NO. 75. 31 
PLATE NO. 18. 
1937 
CASE 55. J. P. EXAMINED MAY 5. 1937. AGE 43, WEIGHT 190 POUNDS 
HE HAS CONTINUED TO CUT STONE SINCE PREVIOUS EXAMINATION. 
COM PLAI NS OF SHO RTN ESS OF BREATH AND PAINS IN THECHEST. SILI- 
COSIS AND BEGINNING TUBERCULOSIS. 32 
PLATE NO. 19 
1958 
CASE 55. J. P. X-RAY MADE MARCH 1938, INDICATES THE PROGRESS OF 
THE TUBERCULOSIS PROCESS IN EACH LUNG. THERE IS EXTENSIVE 
DISEASE IN THE RIGHT LUNG WITH CAVITY FORMATION. THE FLUID 
LEVEL CAN BE SEEN IN THE LARGE CAVITY IN THE MIDDLE PORTION 
OF THE RIGHT LUNG. SPUTUM CONTAINED TUBERCLE BACILLI. 
NOTE.—PATI ENT DIED IN MAY 1938. 33 
plate no. 20. 
1925 
CASE—. D.S. EXAMINED 1925. SCOTCHMAN. AGE 39. HAS CUT G RAN ITE 
WITH HAND-PNEUMATIC TOOL FOR 20 YEARS. FOR THE PAST 2 YEARS 
HAS BEEN A SANDBLASTER. AT PRESENT HE HAS NO COMPLAINTS. 34 
PLATE NO. 21 
1931 
CASE—. D. S. EXAMINED AUGUST 1931. PATIENT HAS LOST WEIGHT AND 
APPEARS TO BE BREAKING DOWN WITH TUBERCULOSIS; HOWEVER, HE 
HAS NO EVIDENCE OF TOXEMIA. HIS HABITS ARE EXEMPLARY AND 
HE IS AN ARDENT GOLFER. COMPLAINS OF DYSPNEA ON EXERTION. 
X-RAY SEEMS TO INDICATE THAT THERE IS A PULMONARY INFECTION. 35 
PLATE NO. 22. 
1933 
CASE . D. S. EXAMINED 1933. THIS X-RAY WAS PROVIDED BY THE 
BARRE CITY HOSPITAL. IT WAS MADE WHEN THE PATIENT WAS ILL 
WITH TUBERCULOSIS. HE DIED IN 1933. 36 
An Italian (A-B group), see plates 23 and 24, was 30 years of age 
at the time the 1924 X-ray was made. The examination was negative 
PLATE NO. 23. 
1924 
CASE 266. E. M. EXAMINED JULY 22, 1924. ITALIAN. AGE 30. GRANITE 
CUTTER 1 1 YEARS. SAN DBLASTE R3Y EA RS. USES POSITIVE PRESSU RE 
HOOD. HEIGHT 62 INCHES, WEIGHT 157 POUNDS. CHEST EXAMINA- 
TION NEGATIVE. X-RAY NO. 15. 
and the X-ray did not show any signs of silicosis. He had not worked 
for a year previous to the examination in 1937 because of rheumatic 
fever. At the time of examination he complained of loss of 36 pounds 37 
in weight, fever, cough and expectoration, night sweats, and pains in 
the joints. There were rales in the lower portions of both lungs and 
the sputum contained tubercle bacilli. He died in 1938. 
Plate no. 24. 
1937 
CASE 266. E. M. EX AM 1N ED AUGUST 3, 1 937. AGE 43, WEI GHTI 21 POU N DS. 
HE CONTINUED TO WORK AS A SANDBLASTER UNTIL 5 YEARS AGO. 
WHEN HE BECAME FOREMAN. HE HAS NOT WORKED DURING THE 
PAST YEAR BECAUSE OF ILLNESS. COMPLAINS OF DYSPNEA, LOW 
BLOOD PRESSURE. COUGH AND EXPECTORATION, AFTERNOON TEM- 
PERATURE AND NIGHT SWEATS AND PAINS IN THE JOINTS. ARTHRI- 
TIS, SILICOSIS. AND TUBERCULOSIS. SPUTUM CONTAINED TUBERCLE 
BACILLI. 
NOTE.—PATIENT DIED MARCH 1938. 38 
Plates 25 and 26 illustrate case No. 1, a Scotchman (A-B group), 
who was 56 years of age at the time of the 1925 examination. He 
had cut stone for 14 years in Scotland where he said that the hand- 
PLATE NO. 25. 
1925 
CASE 1. H. B. EXAMINED FEBRUARY 24, 1925. SCOTCHMAN. AGE 56. 
HEIGHT 69 INCHES, WEIGHT 176 POUNDS. GRANITE CUTTER 39 YEARS. 
14 YEARS IN SCOTLAND, POSSIBLY WITH LOW DUST EXPOSURE. X- 
RAY NO. 78. EARLY SILICOSIS. 
cutting had not produced as much dust as the pneumatic tools. 
The X-ray showed signs of very early silicosis. In 1937 he was found 
to have a tuberculous infection with the evidence of toxemia. 39 
PLATE NO. 26. 
1938 
CASE 1. H. B. AGE 68. CUT G RAN ITE FO R MO RE THAN 50 YEARS. COM- 
PLAINED OF COUGH AND EXPECTORATION, HEMOPTYSIS. PAINS IN 
THECHEST, FEVER, LOSS OF WEIGHT, AND SEVERE DYSPNEA. ADVANCED 
SILICOSIS AND TUBERCULOSIS. CAVITATION .IN THE RIGHT UPPER 
LOBE. SPUTUM CONTAINED TUBERCLE BACILLI. 
NOTE.— PATI ENT DIED AUGUST 19. 1938. 40 
PLATE NO. 27. 
1924 
CASE 57. H. C. EXAMINED DECEMBER 11. 1924. CANADIAN. AGE 40, 
HEIGHT 70 INCHES, WEIGHT 160 POUNDS. G RAN ITE CUTTER 21 YEARS. 
EARLY SILICOSIS. X-RAY NO. 36. 41 
PLATE NO. 28. 
1937 
CASE 57. H. C. EXAMINED MAY 6, 1937. AGE 53. HE CONTINUED TO CUT 
GRANITE EXCEPT FOR SHORT INTERVALS DURING THE DEPRESSION. 
QUIT WORK IN NOVEMBER 1936, BECAUSE OF ILLNESS. COMP LA INE D OF 
DYSPNEA, WHICH WAS EXTREME ON SLIGHT EXERTION, COUGH AND 
EXPECTORATION. WHICH WAS BLOODY AT TIMES, AFTERNOON TEM- 
PERATURE. LOSS OF WEIGHT, AND WEAKNESS. CHEST SHOWS 
EVIDENCE OF ADVANCED TUBERCULOSIS AND SILICOSIS. SPUTUM 
CONTAINED TUBERCLE BACILLI. 
NOTE.—PATIENT DIED FEBRUARY 1938. 
In Table 1 is given a tabulation of the cases studied in 1937 who 
continued at their same occupations. The estimate of progress has 
been indicated in the last three columns: 42 
Initials 
Case 
No. 
1937 
age 
Years in 
occupa- 
tion by 
1937 
Diagnosis (1925) 
Diagnosis (1937) 
Progress 
Remarks 
E. M 
248 
34 
14 
Negative for silicosis .... 
Nmp 
Latent. 
G. C 
300 
39 
15 
do 
J. P 
55 
37 
11 
do__ 
Out 5 years for military service. 
E. C 
258 
47 
21 
do 
I. M 
283 
47 
28 
do 
G. S 
232 
37 
16 
do 
J. P 
60 
40 
23 
More fibrosis than normal 
- ...do 
E. B 
43 
52 
26 
do 
J. 0 
259 
37 
16 
Negative for silicosis 
do 
C. C . 
253 
43 
15 
do 
...do. .. 
C. G 
276 
45 
25 
do 
J. D 
331 
50 
30 
Early silicosis _ . 
__ __do 
J. L 
148 
63 
48 
do 
Irregular employment for last 
5 years. 
S. L 
30 
43 
26 
Moderate silicosis.. _ ... 
L. () 
249 
37 
21 
Negative for silicosis 
Early silicosis 
C. B 
224 
44 
19 
do 
do 
I. L ... ... 
202 
31 
15 
. . do. 
A. C 
94 
41 
23 
Early silicosis ... .. _. ... 
A. A 
78 
50 
33 
. ..do 
do 
P. P 
286 
54 
21 
Moderate silicosis ... __ 
do 
do 
J. B 
238 
52 
27 
Early silicosis 
A. D 
330 
47 
26 
Negative for silicosis .......... . _ 
do 
J. L 
6 
46 
28 
do 
Tabes. 
C. W 
4 
50 
26 
do 
do _ _ 
A. R 
201 
52 
31 
Early silicosis.. _ _ 
Syphilis and suspected tuber- 
culosis. 
E.S 
244 
53 
28 
do 
W. T 
263 
53 
28 
do 
do . . 
A. C_.__ 
255 
50 
33 
do 
G. R 
313 
55 
33 
. ..do 
P. B 
95 
37 
20 
Negative for silicosis _ _ 
do 
F. R 
220 
57 
37 
Early silicosis . . 
Suspected tuberculosis. 
O. A 
27 
53 
21 
do.. .. . . . . 
M. B 
261 
47 
32 
Negative for silicosis 
Advanced silicosis 
Do. 
N. B 
278 
55 
33 
Early silicosis .. ._ ... 
do. _ 
R. S 
227 
60 
33 
Moderate silicosis .. 
do 
J. M 
32 
52 
33 
.. ...do 
___ _do. 
L. C 
298 
51 
27 
Early silicosis ... ._ 
do 
J. M 
219 
59 
34 
Moderate silicosis 
do_ 
P. B 
87 
64 
44 
do 
do. _ 
Do. 
Table 1. Cases of granite cutters (group A-B) who continued at occupation 43 
99 
336 
186 
3 
107 
8 
2,r)0 
230 
194 
135 
500 
11 
501 
55 
57 
176 
266 
91 
306 
1 
63 
9 
264 
225 
138 
24 
65 
47 
Advanced silicosis—tuberculosis 1940 
Marked 
Suspected tuberculosii 
70 
55 
62 
45 
44 
44 
56 
35 
36 
20 
20 
23 
Advanced silicosis 
do.. 
do. 
Moderate--. . - - 
J. O 
... .do. 
Marked 
Suspected tuberculosis. Died 
Advanced silicosis—tuberculosis 
do 
1940. 
Died 1939. 
do— - 
do 
Died 1937. 
Moderate silicosis - ------ 
Moderate 
Suspected tuberculosis. 
52 
50 
55 
/ 47 
25 
Advanced silicosis—_ - -- -.- .. 
Marked 
Do. 
33 
40 
j 28 
39 
1 35 
Advanced silicosis—tuberculosis __ 
do— 
do 
do 
Died 1937. 
do__ 
do 
Died 1933. 
{(1933) 
56 
/ 56 
do 
do 
Died 1938. 
J . J 
Advanced silicosis 
Advanced silicosis (1931—tuberculosis) — 
do 
Died 1933. 
\ (1933) 
43 
53 
63 
43 
54 
46 
68 
J 
26 
34 
49 
27 
37 
30 
50 
52 
35 
33 
32 
22 
Advanced silicosis—tuberculosis 
do. 
Died 1938. 
do 
Died 1937. 
do. _ 
do. 
Died 1939. 
do 
do 
Died 1937. 
do__ 
_ ...do. 
Died 1939. 
do. ._ 
do-, 
do. - 
do 
Died 1937. 
do,_ 
do 
Do. 
63 
53 
55 
40 
57 
do 
do. 
do. 
Do. 
do 
do -- 
do. 
Do. 
do.. 
do 
Died 1938. 
... _do._ 
.do. 
41 
do --- 
do 
Died 1937. 44 
GRANITE CUTTERS, GROUPS A-B, WHO CHANGED TO NON DUSTY 
OCCUPATIONS 
One of the unusual features of silicosis in granite workers is its 
progress after the cessation of exposure to dust, if the condition was 
PLATE NO. 29 
1925 
CASE 103. R. A. EXAMINED DECEMBER 11. 1925. ITALIAN. AGE 42. 
GRANITE CUTTER 30 YEARS. HEIGHT 66 INCHES, WEIGHT 159 POUNDS. 
EARLY SILICOSIS. 
well established, its course and prognosis seemed to be altered very 
little by the removal of the worker to a nondusty occupation. It is 
questionable if the early cases without any infection exhibit this 
characteristic; however, more information is needed on this phase of 
the subject. A change in occupation did not seem to materially 45 
lessen the chances of escaping a final tuberculous complication in the 
more advanced cases of silicosis. This was exemplified in the granite 
manufacturers, most of whom had been stone cutters before starting 
in business for themselves, and evidently had silicosis. It was found 
PLATE NO. 30. 
1938 
CASE 13. R. A. EXAMINED MAY 29, 1938. HAS NOT CUT GRANITE FOR 7 
YEARS. HAS BEEN A GRANITE SALESMAN. COMPLAINSOF BRONCHITIS 
AND DYSPNEA. WE IG HT 179 POU N DS. ADVANCED SILICOSIS. 
that the death rate of granite manufacturers from tuberculosis was 
almost the same as for granite cutters. In most instances, their 
social and economic conditions were even better than that of the 
granite cutters, which incidentally was above the average for indus- 
trial workers outside the granite industry. 46 
The progress of silicosis after cessation of exposure has been referred 
to by other investigators. In South Africa, it was found that “a 
steady fall over a period of years in dust concentration is not associated 
plate no. 31 
1925 
CASE 170. J.S. EXAMINED JULY 3. 1925. SCOTCHMAN. AGE 51. HEIGHT 
68 INCHES. GRANITE CUTTER 35 YEARS, 24 YEARS WITH PNEUMATIC 
TOOL. SLIGHT INCREASE IN FIBROSIS. 
with the corresponding fall in the silicosis incidence.’’5 Britten 6 
reports two cases of workers who had worked in dusty occupations 
5 South African Institute of Medical Research, Annual Report, Year ending 1925. 
4 Britten, James A.: Silicosis a Modern Factory Hazard. Industrial Hygiene, September 1924. 47 
for 7 and 8 years and later changed to nondusty occupations where 
they worked 8 and 9 years. They developed pulmonary symptoms 
and were found to be suffering from silicosis and tuberculosis. 
Plate no. 32 
1937 
CASE 170. J. S. EXAMINED JUNE 22, 1937. AGE 63, WEIGHT 148 POUNDS. 
PATIENT CONTINUED TO CUT GRANITE 4 YEARS, AND SINCE THAT 
TIME HAS BEEN WORKING ON A FARM. MODERATE SILICOSIS AND 
SUSPECTED TUBERCULOSIS. 
Case 93, an Italian, changed from the occupation of carver to drafts- 
man in 1926 and worked at his new trade in his home. He had been 
an expert carver and statuary cutter. His mode of living and habits 
were exemplary. The 1924-25 X-rays indicated that he had a moder- 48 
ate amount of silicosis. The 1937 X-ray indicates that there was an 
advanced tuberculosis present, involving both lungs. He complained 
of weakness, cough and expectoration, dyspnea, loss of weight, tempcr- 
PLATE NO. 33. 
1924 
CASE 93. J. B. EXAMINED MAY 26, 1924. ITALIAN. AGE 41, HEIGHT 66 
INCHES. WEIGHT 147 POUNDS. STATUARY AND DESIGN CUTTER 21 
YEARS. MODERATE SILICOSIS. X-RAY NO. 68. 
ature,and night sweats. Sputum contained tubercle bacilli. Patient 
died in September, 1937. 
The change in the type of heart shadow as shown in the X-rays 
of this patient is consistent with experience in tuberculosis among per- 49 
sons not in dusty trades. Apparently it results from toxemia of 
tuberculosis. 
PLATE NO. 34 
1957 
CASE 93. J. B. EXAMINED MAY 26, 1937. AGE 54, WEIGHT 130 FOUNDS. 
SINCE 1926 HE HAS BEEN WORKING AS A DRAFTSMAN IN HIS OWN 
HOME, COMPLAINS OF WEAKNESS, COUGH AND EXPECTORATION, 
DYSPNEA AND LOSS OF WEI G HT. CHEST SHOWS EVI DENCE OF SILICOSIS 
AND ADVANCED TUBERCULOSIS. 
NOTE.—PATIENT DIED SEPTEMBER 1937. 
Case 40, an Italian, was 48 years of age when he was examined in 
1924 and had cut granite for 25 years. X-ray showed evidence of 
early silicosis. He stopped work in 1930 and did not engage in any 50 
dusty occupation. Two years prior to the 1937 examination lie began 
to lose weight and this continued until he was emaciated. He com- 
plained of weakness, marked dyspnea, cough and expectoration, and 
PLATE NO. 35, 
1924 
CASE 40. J. B. EXAMINED DECEMBER 5, 1924. ITALIAN. AGE 48, HEIGHT 
66 INCHES, WEIGHT 162 POUNDS. G RAN ITE CUTTE R25 YEA RS. MODER- 
ATE SILICOSIS. 
pains in the chest. Sputum contained tubercle bacilli. Patient died 
in August 1938. 
In the 1937 X-ray there are unmistakable signs of advanced tuber- 
culosis, with a cavity in the base of the right lung. The relatively 
clear apices are remarkable. 51 
A visit to the patient in 1938 revealed that he was bedfast and 
extremely emaciated and weak. His daughter has developed active 
tuberculosis during the past year. 
PLATE NO. 36. 
1937 
CASE 40. J. B. EXAMINED APRIL 29, 1937. AGE 62. CONTI NUED TO CUT 
GRANITE UNTIL 1930. HAS NOT WORKED SINCE THAT TIME. PRESENT 
ILLNESS BEGAN 2 YEARS AGO WITH LOSS OF WEIGHT, WEAKNESS, AND A 
PRODUCTIVE COUGH. SPUTUM POSITIVE FOR TUBERCLE BACILLI. 
CHEST SHOWS ADVANCED TUBERCULOSIS, WITH CAVITATION [IN THE 
RIGHT BASE, AND SILICOSIS. APICES RELATIVELY CLEAR. 
NOTE.—PATIENT DIED AUGUST 11, 1938. 
Case 105, plates 37 and 38, an Irishman who was 61 years of age 
at the time of the 1937 examinations. The 1925 X-ray revealed more 
fibrosis than normal but otherwise nothing of interest. He had been 52 
cutting granite for 13 years at that time, which means that he did not 
start at the trade as early in life as the average granite cutter. He 
stopped working in the dust in 1932 at which time he had been exposed 
PLATE NO. 37. 
1925 
CASE 105. J. G. EXAMINED FEBRUARY 16, 1925. IRISHMAN. AGE 49, 
HEIGHT 68 INCHES, WEIGHT 141 POUNDS. GRANITE CUTTER (SURFACE 
MACHINE OPERATOR) 13 YEARS. MORE FIBROSIS THAN NORMAL. 
X-RAY NO. 66. 
to dust for 20 years. He changed to a nondusty trade and continued 
working until a few months prior to the 1937 examination. There 
was evidence of advanced tuberculosis with cavity formation in the 
left upper lobe. He complained of general weakness, fever, cough, 53 
loss of weight and strength, night sweats, and pains in the chest. The 
sputum contained tubercle bacilli. The patient died in 1937. 
Plate No. 38. 
1937 
CASE 105. J. G. EXAMINED MAY 29, 1937. AGE 61, WEIGHT 130 POUNDS. 
PATIENT CONTINUED TO CUT GRANITE UNTIL 5 YEARS AGO. SINCE 
THAT TIME HE HAS BEEN A LABORER IN A CEMETERY, ALTERNATING 
BETWEEN GENERAL WORK AND GRAVE DIGGING (NOT DRY). COM- 
PLAINS OF GENERAL WEAKNESS, PAINS IN THE CHEST, AND A PRODUC- 
TIVE COUGH. SPUTUM POSITIVE FOR TUBERCLE BACILLI. HAS NOT 
WORKED FOR LAST FEW MONTHS DUE TO ILLNESS. CHEST SHOWS 
EVIDENCE OF TUBERCULOSIS IN BOTH LUNGS WITH CAVERNOUS 
BREATHING I N THE LEFT U PPER LOBE. TUBERCULOSIS AN DSI LICOSIS 
NOTE.—PATIENT DIED IN NOVEMBER 1937. 
This case is of interest in that the patient did not start cutting 
granite as early as is usual with granite cutters. 54 
Initials 
Case 
No. 
1937 
age 
Years 
in dust 
Years 
out of 
dust 
Diagnosis (1925) 
Diagnosis (1937) 
Progress 
Remarks 
L. L 
314 
62 
88 
104 
175 
97 
255 
240 
316 
53 
170 
82 
103 
93 
40 
105 
301 
226 
41 
53 
44 
48 
46 
50 
50 
48 
60 
52 
63 
53 
54 
54 
62 
61 
55 
52 
6 
24 
19 
12 
19 
21 
17 
30 
27 
21 
39 
22 
35 
23 
31 
20 
27 
27 
13 
13 
6 
8 
15 
12 
15 
9 
11 
7 
8 
12 
7 
11 
7 
5 
12 
10 
More fibrosis than normal 
Negative for silicosis—latent tuberculosis 
Early silicosis.. __ 
None for sili- 
cosis. 
Fibrosis undoubtedly due 
to old tuberculosis. 
Out of dust 20 years. 
Asthma. 
Suspected tuberculosis. 
Do. 
Do. 
Died 1937. 
Do. 
Do. 
R. M 
do__ 
A M 
-do 
J. M 
Negative for silicosis. . _ 
Moderate 
More fibrosis than normal 
A. C 
Early silicosis . 
Moderate silicosis... 
Moderate 
- --do. 
do 
do _ 
v, A _ 
do 
J. o 
do.. 
R A 
do._ 
Advanced silicosis 
do. 
J. Jj _ _ _ _ 
J. B 
Moderate silicosis .. 
Advanced silicosis—tuberculosis 
do 
do 
do. 
do._ 
Table 2. Cases of granite cutters (groups A-B) who changed to nondusty occupations 55 
Table No. 2 has been made from histories of cases studied in 1937 of 
former granite cutters who changed to nondusty occupations. There 
was definite evidence of progress of silicosis in all patients except one. 
This patient had an early tuberculous lesion in the apex of the right 
lung and some fibrosis associated with it. He had been exposed to 
dust only 6 years and had been out of it for 13 years. It is not possible 
to state that the condition has progressed as he had no signs of silicosis 
in 1925 and 1937—only the tuberculous lesion. 
In this group the progress seems to have been proportionate to the 
extent of dust exposure. 
LOW DUST EXPOSURE, GROUPS C D 
The following cases are presented as controls inasmuch as they are 
those workers who were exposed to a dusty atmosphere of the average 
plant dustiness (20 million particles per cubic foot) or less (groups C 
and D). These groups of workers were exposed to the same type 
of dust as were A and B but in much less concentration and the result 
of exposure is quite different. The difference in the amount of sick- 
ness and death rates as well as the incidence of silicosis and tuber- 
culosis has been stressed. The variation in exposure is one of intensity 
inasmuch as the dust was the same. This points out the importance 
of dust counts to determine the extent of dustiness. Exposure to 
silica dust in certain trades did not produce silicosis, and for this reason 
the etiology of silicosis was obscure since exposure in other trades 
produced the condition. The difference in effect of silica dust was 
found to be a matter of extent of concentration, when methods of dust 
counting were evolved and put into use. 
The first case presented in this series (see plate No. 39), did not 
have an X-ray at the time of the original examination. His age and 
length of service as well as his present chest condition is a great con- 
trast to what has been shown in those workers who had dust exposure 
in dangerous amounts. He has been a machinist in the granite 
industry for 55 years. His condition was found to be about the same 
as it was in 1925 at the time of the first examination. He continues 
at his work without regard for his advanced years. 
Plate No. 40 illustrates case 318. This man worked as a lumper 
and was exposed to the general plant atmosphere which averaged 20.2 
million particles of dust per cubic foot. He was 55 years old at the 
time of the 1937 examination. A comparison of his X-ray with that 
of a granite cutter of the same age will reveal quite a difference. This 
worker has some signs of fibrosis but not sufficient to warrant a 
diagnosis of silicosis. 
X-rays of case 171 were made in 1935 and 1938. (See plates Nos. 
41 and 42.) He cut granite for 11 years but apparently this was 56 
insufficient in time to produce evidence of silicosis. Ho changed to 
the occupation of sandblaster and used good protective equipment. 
As a result, he does not present evidence of silicosis in early 1938. 
PLATE NO. 39. 
1937 
CASE 288. F. E. L. EXAMINED APRIL 10, 1925. AMERICAN. AGE 61. 
HEIGHT 64 INCHES, WEIGHT 129 POUNDS. MACHINIST IN THE GRANITE 
INDUSTRY 43 YEARS, WORKING IN A SEPARATE ROOM. CHEST NEGA- 
TIVE. 
EXAMINED AUGUST 6, 1937. AGE 74, WEI GHT 125 POU N DS. HE HAS CON- 
TINUED TO WORK AS A MACHINIST SINCE PREVIOUS EXAMINATION. 
CHEST SHOWS SLIGHT FIBROSIS. CONSISTENT WITH HIS AGE. 57 
Table 3 summarizes the changes found in the low-exposure group 
(C-D). Those cases showing changes were for the most part workers 
who had been exposed to greater amounts of dust. The two with 
moderate progress had had exposure of this type—one for 20 years. 
Plat no 40. 
1937 
CASE 318. F. L. EXAMINED AUGUST 25, 1924. AMERICAN. AGE 43 
HEIGHT 68 INCHES, WEIGHT 148 POUNDS. LUMPER 20 YEARS. CHEST 
ESSENTIALLY NEGATIVE. 
RE-EXAMINED AUGUST 13, 1937. HAS CONTINUED WORK AS A LUMPER 
SINCE 1924. CHEST SHOWS MORE FIBROSIS THAN NORMAL. 58 
Plate no. 41 
1926 
CASE 171. P. L. EXAMINED MAY 26, 1926. AMERICAN. AGE 29, HEIGHT 
65 INCHES, WEIGHT 143 POUNDS. GRANITE CUTTER 11 YEARS. SAND' 
BLASTER AND LETTERER 4 YEARS. CHEST SHOWS SLIGHT FI BROSIS. 59 
PLATE NO. 42 
1938 
CASE 171. P. L. EXAMINED JUNE 19, 1938. AGE 40, WEIGHT 161 POUNDS 
HE HAS CONTINUED TO WORK AS A SANDBLASTER SINCE PREVIOUS 
EXAMINATION, AND FOR PAST 5 YEARS HE HAS USED CARBORUNDUM 
AND STEEL IN THE SANDBLAST PROCESS. HE HAS BEEN WEARING A 
GOOD POSITIVE-PRESSURE AIR HOOD SINCE HE BEGAN TO WORK AT 
SANDBLASTING. CHEST SHOWS MORE FIBROSIS THAN NORMAL. 60 
PLATE NO. 43. 
1937 
CASE 310. P. P. EXAMINED JANUARY 9, 1925. ITALIAN. AGE 37, HEIGHT 
67 INCHES, WEIGHT 158 POUNDS. G RAN ITE LU MPE R 1 2 YEA RS. CHEST 
NEGATIVE. 
EXAM INED AUGUST 9, 1937. AGE 50. WEIGHT 163 POUNDS. SINCE PRE- 
VIOUS EXAMINATION HE HAS CONTINUED TO WORK AS A LUMPER 
EXCEPT FOR BRIEF INTERVALS. CHEST NEGATIVE. 61 
Initials 
Case 
No. 
1937 
age 
Years in 
occupa- 
tion by 
1937 
Diagnosis (1925) 
Diagnosis (1937) 
Progress 
Remarks 
34 
1 
Negative for silicosis.. .. . . 
None . ... ... 
36 
1 
....Mo 
do 
54 
3 
do 
do 
37 
7 
do 
37 
13 
do 
n n 
280 
32 
15 
do 
do 
2 
34 
15 
do ... 
do . 
Cr T 
68 
38 
16 
do .... 
do. 
. do ------- 
A. T 
246 
48 
20 
do 
.. . do 
812 
65 
46 
do . 
. _ do.. .......... 
do 
818 
55 
33 
do 
do 
40 
22 
do 
do 
50 
24 
.. ... do ..... 
do 
299 
35 
17 
Latent tuberculosis right apex 
Slight.. 
181 
34 
15 
do 
More fibrosis than normal 
do 
Sandblaster-protected. 
A. N 
303 
34 
16 
do 
....do 
do 
288 
74 
55 
do 
..do .. .... 
do 
47 
30 
do 
do 
do . 
Cut granite 9 years. 
E L 
182 
45 
26 
do - 
do 
do 
Cut granite 14 years. 
P. L 
171 
41 
23 
do 
do 
do 
Cut granite 11 years. 
Cj W 
108 
53 
34 
do , 
do 
do.. - 
Cut granite 20 years. 
21 
do 
M. D 
77 
38 
15 
.“...do.. 
do 
do 
Sandblaster—protected. 
61 
22 
do 
do _ 
58 
26 
do 
....do 
do.. . . 
53 
33 
do.. 
T- C 
96 
46 
28 
.... do ...... 
.. ..do 
29 
do 
do.. 
Cut granite 15 years. 
N. D 
241 
63 
30 
do 
do 
do 
J W 
304 
51 
31 
More fibrosis than normal 
do - 
do 
Cut granite 9 years. 
FT T 
36 
46 
16 
do 
do 
Lung abscess 1924. 
j. p 
48 
47 
22 
Negative for silicosis 
Early silicosis ...... 
Moderate.. 
Formerly an anthracite coal 
miner. 
A. B 
281 
57 
40 
More fibrosis than normal 
do 
do . 
L— 
— 
— 
— 
Table 3.—Low-exposure group (C-D) STATISTICAL SUMMARY 
The following tables 4, 5, and 6, summarize some of the salient facts 
reviewed in the text. It should be borne in mind that this material 
suffers from the restrictions necessarily imposed by any quantitative 
analysis since medical diagnoses of this nature often do not permit of 
exact categorical classification. In general, all cases have been classi- 
fied according to stages of silicosis and tuberculosis, but within the 
limits of those stages there are even finer gradations that are com- 
pletely obscured in these tabular presentations. The author is fully 
cognizant of the questions of statistical validity that arise in this 
connection, but waives those questions in favor of offering some con- 
densed form of this work which would otherwise be impossible. 
Table 4. Granite workers. Chest diagnosis in 1925 compared with 
diagnosis in 1937 according to dust exposure groups 
with 
Diagnosis 
Groups A-B 
who continued 
at occupation 
Groups A-B 
who changed 
to nondusty 
occupations 
Groups C-D 
Total 
1925 
1937 
1925 
1937 
1925 
1937 
1925 
1937 
Tuberculosis—negative 
64 
39 
18 
9 
33 
32 
115 
80 
21 
1 
30 
13 
52 
13 
More fibrosis than normal 
2 
2 
4 
3 
17 
9 
19 
19 
11 
8 
4 
2 
28 
17 
21 
15 
5 
5 
25 
20 
1 
11 
1 
11 
Suspect tuberculosis 
1 
8 
3 
1 
11 
1 
1 
Moderate silicosis _ _ 
2 
1 
2 
6 
2 
6 
Latent tuberculosis.__ 
1 
1 
1 
3 
Negative for silicosis 
1 
1 
1 
3 
21 
5 
26 
21 
5 
26 
— 
Total.. _ ._ _ 
65 
65 
18 
18 
33 
33 
116 
116 
Negative 
21 
1 
1 
1 
30 
14 
52 
16 
2 
2 
4 
3 
17 
9 
19 
20 
11 
8 
4 
2 
29 
17 
21 
16 
5 
6 
25 
22 
1 
35 
I 
42 
Table 4, the first of the series, presents the diagnoses with respect 
to silicosis and tuberculosis of 116 granite workers who were available 
for examination both in 1925 and 1937. These workers are divided 
iu three groups, as in our previous discussion, according to dust 63 
exposure. The first two groups, both of dust exposure class A-B, 
are arranged according to those workers who continued at their occu- 
pations until the time of reexamination in 1937 and those who changed 
their occupations subsequent to the first examination. It is clear 
from this table that both these A-B groups progressed in relatively 
impressive numbers, from the milder forms of silicosis to the more 
severe forms and often suffered the further complication of tuber- 
culosis. In fact, since tuberculosis was so often present in the 1937 
diagnoses, it was thought advantageous to relate the silicosis diag- 
nosis to the tuberculosis diagnosis in this table. The 33 workers com- 
prising group C-I) show slight changes from early to later forms of 
fibrosis and silicosis, but it is clear that they are on the whole com- 
paratively unaffected. Also in this group, there was only one case 
of latent tuberculosis and this worker did not have silicosis. 
Table 5.— Granite workers. Progress from 1925 to 1937, compared with 
initial diagnosis 
GROUPS A-B (EXPOSURE OVER 20 MILLION PARTICLES) WHO CONTINUED AT 
OCCUPATION 
Initial diacnosis with respect to 
Progress in 12 years 
Tuberculosis complica- 
tions 
Known 
deaths 
to 1940 
silicosis (1925) 
None 
Slight 
Moder- 
ate 
Marked 
Active 
Latent 
Suspect 
1 
2 
31 
31 
21 
1 
8 
18 
1 
2 
14 
4 
2 
1 
3 
2 
More fibrosis than normal.. . 
2 
9 
11 
fi 
2 
5 
6 
15 
12 
3 
10 
1 
1 
1 
GROUPS A-B WHO CHANGED TO NONDUSTY OCCUPATIONS 
1 
3 
6 
8 
5 
1 
3 
3 
Negative _ .. 
1 
1 
3 
1 
Early silicosis _ _ _ _ _ 
5 
3 
5 
5 
3 
3 
GROUP C-D 
Total- 
13 
18 
2 
1 
13 
16 
2 
1 
1 
1 
Table 5 presents the progress of disease in these workers compared 
with the initial diagnoses in 1925; again the table is divided according 
to dust count groups. In virtually all of the cases in the A-B groups, 
progress is moderate or marked; almost all of the workers in the C-D 
group progressed not at all or only slightly from 1925 to 1937. Of a 
total of 82 workers in the A-B group, 39 were active, latent, or suspect 
cases of tuberculosis as well; of this group, there were 21 known 64 
deaths at the time of writing. There were no deaths in the C-D 
group, and only one case of latent tuberculosis. The reader should 
be again cautioned to interpret this table broadly since it is often 
difficult to classify degree of progress of silicosis to meet the require- 
ments of a statistical table. The general conclusion to be drawn from 
these remarks is that apparently a high correlation exists among three 
interdependent factors: severity of original diagnosis, degree of prog- 
ress, and dust-count group to which the worker belongs. 
Figure 4 illustrates in graph form the comments that have been 
made on table 5. Marked and moderate degrees of progress account 
for almost all cases in the first two groups, while for group C-D, 
almost all cases were only slightly, or not at all, affected. 
Table 6 is intended to show progress of disease in relation to the 
length of service, according to dust-count groups. It is evident from 
this table that those who serve longest are most subject to change in 
diagnosis from the less to the more advanced stages of the disease, 
particularly in the A-B group. This fact was suspected, of course, 
but it is interesting to note that statistical analysis confirms the 
suspicion. 
A word should be added to explain that no attempt is made to offer 
much statistical interpretation since the figures are too small to justify 
elaborate computations. The tables and charts are presented as a 
visual aid to summarize quickly the eases discussed more fully in the 
text. 
Table 6.—Progress of silicosis by years in occupation and dust 
exposure groups 
Groups A-B who con- 
tinued at occupation 
Groups A-B who 
changed to nondusty 
occupations 
Groups C-D 
Years in occupation to 1937 
0-9 
10- 
19 
20- 
29 
30- 
39 
40 
and 
over 
To- 
tal 
0-9 
10- 
19 
20- 
29 
30- 
39 
40 
and 
over 
To- 
tal 
0-9 
10- 
19 
20- 
29 
30 
39 
40 
and 
over 
To- 
tal 
Progress in silicosis—Total _ 
8 
27 
21 
9 
65 
1 
4 
9 
4 
18 
4 
9 
11 
6 
3 
33 
1 
i 
1 
1 
4 
4 
3 
1 
1 
13 
Slight 
1 
1 
2 
2 
1 
3 
5 
5 
1 
13 
6 
18 
5 
2 
31 
2 
3 
1 
6 
1 
1 
2 
8 
16 
31 
5 
3 
8 
Tuberculosis com plica- 
tions—Total 
1 
8 
10 
11 
30 
1 
— 
5 
3 
9 
— 
1 
i 
2 
4 
2 
8 
1 
2 
3 
1 
1 
1 
1 
i 
6 
6 
9 
21 
4 
1 
5 
5 
8 
5 
2 
1 
3 65 
NONE 
(Ceased occupation) (Continued occupation) 
GROUP C-D GROUP A-B GROUP A-6 
SLIGHT 
MODERATE 
MARKED 
NONE 
SLIGHT 
MODERATE 
MARKED 
NONE 
SLIGHT 
MODERATE 
MARKED 
0 5 10 15 20 25 30 35 40 45 50 55 
PERCENT OF CASES IN EACH PROGRESS GROUP 
Figure 4.—Progress from 1925 to 1937 by dust count groups GENERAL STATEMENT AND RECOMMENDATIONS 
EXTENT OF DUST EXPOSURE IN THE PAST 
The question of the approximate magnitude of exposure of all 
workers in granite-cutting processes throughout their period of in- 
dustrial life is a most important one, if wo are to relate this exposure 
to its effect on health and to have a basis upon which sensible recom- 
mendations for future control of the hazard may be constructed. 
The use of hand pneumatic tools in granite cutting in the United 
States first became general approximately 40 years ago. There seems 
every indication, both from such observations as have been made as 
to the amount of dust caused by hand tools (not pneumatic) and the 
much lower tuberculosis rate found in granite cutting before intro- 
duction of pneumatic tools, that the dustiness was very much less 
than today. 
The intensity of exposure during the period since the use of hand 
pneumatic tools became general is a matter more or less of suppo- 
sition, except for certain facts which have been gained from a personal 
study of the industry and from information obtained from the workers 
themselves. It seems certain that the introduction of pneumatic 
cutting was gradual, so that there was no abrupt change in dustiness 
during a short period of time. On the other hand, there is definite 
information to the effect that there were a smaller number of sheds 
and greater concentration of workers in these sheds 20 to 25 years 
ago than is found at the present time. The use of ventilating devices 
for the removal of dust from surface-cutting machines belongs to a 
still more recent period and there is little doubt that the efficiency 
of these devices had not been improved until in very recent years. 
These several conditions would indicate that in the early period of 
use of the hand pneumatic tool there was probably a greater amount 
of dustiness, especially in the general plant atmosphere, than exists 
at the present time. On the other hand, the fact that the dust 
counts for the hand pneumatic-tool operators were taken near the 
source of dust inclines to the belief that conditions for these operators 
individually have not materially changed since the introduction of 
the pneumatic tool. 
PRACTICABLE LIMITS OF DUSTINESS 
On the basis of the foregoing statements of the past record of dust 
exposure of granite workers, if we may accept them in a general way, 67 
and our more accurate knowledge of the present exposure, together 
with the information obtained from the mortality and morbidity 
studies, it is possible to form some rough ideas of the limits of dusti- 
ness which may be regarded as reasonably safe from a health 
standpoint. 
In estimating such limits consideration must be given to the record 
of tuberculosis and other sickness in the four dust-count groups, each 
having a known concentration of dust exposure. It was found that 
the A and B groups show unmistakable indications of the serious 
effect of the hazard. In those groups the average dustiness was from 
40 to 60 millions of particles per cubic foot of air. Group C, which 
represented the occupations with a dust count equal to that of the 
general plant atmosphere, showed an average of about 20 million 
particles. There was little indication in the study as a whole of 
any serious effect on the men in this group. The death certificates 
showed, to be sure, unusually high proportionate mortality from tuber- 
culosis among polishers and lumpers, who fall into group C. Con- 
fusion between occupations or change in later life from cutters to a 
less exacting occupation may explain part or all of the excess. But one 
would hesitate to be positive that no harm would come to persons 
working for many years under a concentration of 20 million particles. 
In group D, where the average concentration was 6 million particles, 
there was no indication whatsoever of any unfavorable effects on 
health, either from the physical examinations, the sickness records, 
or such mortality data as were applicable to this group. 
From this line of reasoning, the average dust exposure for groups 
A and B must be considered as definitely harmful to the worker. 
There remains, then, group C in which, with an average exposure of 
20 million particles, there is some question as to the harmful effect, 
and group D, with an average exposure of 6 million and a limit of 9 
million, where no harmful effect is found. Thus it would appear 
that a safe limit lies somewhere between the amount of dustiness 
found in groups C and D or between 9 and 20 million particles. 
THE VENTILATION PROBLEM 
The practicable means of attaining such a limit of dustiness for all 
workers in the plants lies in the provision of adequate ventilating 
devices for hand pneumatic-tool cutters, so arranged as to remove 
the dust practically at its source. Figure No. 5 shows that this 
can be accomplished. 
A few points of particular importance must be brought out. 
First. Observations in certain granite plants in Barre and in 
other cities have shown that local exhaust devices can be economi- 
cally installed which will reduce the dust count for the dust-making 
occupations to less than 20 million particles per cubic foot of air and 68 
the general plant atmosphere to approximately 5 million particles. 
The cost of the devices installed in these plants was not found to be 
prohibitive; in fact, the dust problem had been met adequately in 
th( ise plants with a comparatively small expense. The subject is 
covered fully in an article published in the United States Public 
Health Reports,7 both as to the required amount of air to be ex- 
hausted and the type of ventilating devices used. 
The drawing illustrates the fact that the dust problem in granite 
cutting can be controlled by the use of efficient local exhaust systems. 
This schematic drawing was based on experience in a plant that had 
WITHOUT LOCAL EXHAUST 
WITH A LOCAL EXHAUST 
DUST COUNT IN MILLIONS OF PARTICLES PER CUBIC FOOT OF AIR 
EXHAUST 
HOOD 
APPARENT SAFE LIMIT 
59 
9.5 
GRANITE 
CUTTING 
22.6 
APPARENT SAFE LIMIT 
8.9 
PLANT ATMOSPHERE 
Figure s.—use of Local exhaust Ventilation for hand pneumatic Tool 
Cutters. 
already been using exhaust equipment . A few years after the survey 
on which this was based, dust counts in this plant had increased 
considerably and the reason for the condition was neglect in main- 
taining the exhaust equipment in good condition. The cooperation 
of the State Board of Health by making dust counts at intervals and 
inspection of the equipment will prevent a repetition of such con- 
ditions. 
Second. In observations made both in the plants in which the 
present study was conducted and in the plants in which proper types 
of ventilating devices had been installed, there is evidence of con- 
7 Bloomfield, J. J. A study of the efficiency of dust-removal systems in granite-cutting plants. Public 
Health Reports. 44:2505-2522, 1929. 69 
elusive nature of the necessity for the maintenance of these ventilating 
systems in proper running order through competent supervision of 
intelligent foremen or machinists, if the full value of the devices both 
from an economic and a health standpoint is to be maintained. It is 
impossible to emphasize this point too strongly. In the poor plants 
observed in this study, the ventilating equipment was not only of 
little value, but in the case of many of them, as shown by the compari- 
son of summer and winter dustiness there was an actual menace to 
the workers because dust was blown back through the windows when 
open. Even in the better equipped plants improper placing of ex- 
hausts or clogging due to improper maintenance largely negatived 
the full value of the devices. 
Third. From observations in both types of granite plants, it is 
evident that, insofar as possible, ventilating devices wdiich operate 
irrespective of the attention or desire of the worker himself are most 
desirable, and that common sense education of the worker to under- 
stand and utilize the devices which are provided for the protection of 
his health is a vital necessity. 
Fourth. By segregating in separate rooms or buildings insofar as 
possible, those occupational processes in which little dust is produced, 
less dustiness will result. 
Fifth. Adequate ventilation w ill remove the necessity for the use 
of masks in most instances. There are processes, however, that wall 
require the added protection of hoods and masks. It is fortunate 
that the efficiency of this type of equipment has been established and 
most of the manufacturers of protective devices provide them with 
the stamp of approval of the United States Bureau of Mines on each 
article. When this equipment is necessary, care should be taken to 
provide Bureau of Mines approved devices. 
The control of the intensity of dust exposure of granite workers will 
for the most part solve the important problems of the health hazards 
in this industry. On the other hand, it would seem wise that a check 
should be made as to this expected improvement in health conditions 
by medical supervision of the workers to prevent the entrance into 
the industry of individuals more than usually susceptible to tuber- 
culosis, to remove workers from the industry if tuberculosis does 
develop, and, of most importance, to recognize the development of 
silicosis among these workers. Fortunately, this is being done by the 
State board of health. 
This final question is far from being a simple one, since neither this 
study nor any other observations which have been made with respect 
to granite cutting in the United States give us information as to the 
MEDICAL SUPERVISION 70 
amount of silicosis which may develop without making the worker 
more susceptible to tuberculous infection. 
This study does suggest several broad conclusions which appear to 
bear on this point. In group D, where there was exposure to small 
amounts of silica dust over long periods of time, there w*as no tuber- 
culosis, although fibrosis did exist. On the other hand, the group of 
workers who had left the industry after severe exposure and gone into 
nondusty occupations appeared to develop tuberculosis to almost the 
same degree as workers wrho remained in the industry. This woidd 
incline to the belief that a moderate amount of fibrosis, slow in develop- 
ing, is not incompatible with a long working life and is not a serious 
inconvenience to health; but that the contrary is true of a severe 
exposure even for relatively a short period, and that in these cases 
removal of the worker from the dusty occupation is of no avail. A 
clearer understanding of the factors which bear upon the developing 
silicosis and the susceptibility to tuberculosis must be reached. It is 
desirable that research work should be continued both in the labo- 
ratory and among workers exposed to silica dust to determine some of 
the points which have been raised in this summary. 
What appears to stand out most clearly is that a maximum of dust 
exposure, falling somewhere about 10 million particles per cubic foot 
of air for the dust-making occupations, for a dust which contains 
from 25 to 35 percent of free silica in the form of quartz, is a desirable 
limit, and that it can be obtained by the use of economically practicable 
ventilating devices applied to the source of the dust. 
Reference has been made several times to the varying concentra- 
tions and the chemistry of dust and the futility of trying to make a 
prognosis of the cases by the experience of others with different 
exposure. Table 7is presented to bear out this statement as it shows 
the concentrations that have been accepted as permissible for the 
particular industries in the localities indicated. It can be seen 
readily that there can be no standard of permissible dustiness recom- 
mended for all industries. Separate limits of safety must be worked 
out for each industry presenting dust hazards. 
The results of the studies of silicosis have been salutary. Granite 
manufacturers and workers and the people of Barre alike have wel- 
comed and accepted recommendations based on scientific fact to 
eliminate the dust hazard of the industry. The concerted effort of 
the manufacturers to provide and install equipment to blot out this 
sinister plague of silicosis has been conducive to a better morale. 
Manufacturers, in tackling the dust problem and bringing it 
under control, now have at their disposal scientific advice and 
guidance of the State board of health through its bureau of 
industrial hygiene, with headquarters located in Barre. The lives 
of the workers are prolonged by the creation of better working condi- 71 
tions and their fear of impending disability and ultimate death from 
tuberculosis is removed. Their lurking dread of the ravages of 
silicosis, once accepted with stoical resignation as inevitable, has 
given way to optimism and a happier outlook. In the future, older 
granite workers will gladly permit their sons to follow the trade in 
their footsteps, a thing they have been reluctant to do in the past. 
And likewise the results of the studies are a boon to the manufacturer 
who can face the future with the comforting knowledge that his 
industry will not produce an occupational disease as long as he provides 
and maintains adequate dust removal equipment. The manufacturer 
is assured that highly skilled workers will not be doomed to death 
prematurely because of the hazard of their trade at a time of life when 
they are most useful. At present the industry suffers because there 
is an acute shortage of expert carvers and statuary cutters due to 
premature deaths. The few remaining workers are in great demand 
because of the pressing need of their services; they devote themselves 
longer and more arduously than they wish in order to meet the demand 
for expert craftsmanship. 
Table 7.- Permissible concentrations for the particular industries in the 
localities indicated 1 
Industry 
Percentage silica in the dust 
Permissible 
maximum safe 
dust concentra- 
tion—millions 
per cubic foot 
80. . 
4J-4 
8V> 
6 
Barre granite 3 
31 to 38 
10-20 
35. . 
5-10 
13. 
10-15 
5 
50 
Broken Hill, Australia 2_._ . _ _ 
10 to 17 
14 
1 National Silicosis Conference, Bulletin No. 13, Division of Labor Standards, United States Department 
of Labor. 
2 Based upon engineering practice. 
3 Based upon clinical studies. 
lu conclusion, because many persons outside Vermont confuse the 
granite industry with other stone industries of the State, it is necessary 
to repeat and to emphasize that the present report deals with the dust 
hazards of a particular industry where workers were exposed to a dust 
of known silica content and concentration. The deleterious effects of 
this dust have been known for a long time, the remedy for the hazard 
a much shorter time. It is gratifying to observe that there is a con- 
certed effort and determination to make the industry safe. If the 
present trend continues, silicosis in the granite industry of Vermont 
will become a matter of history.