Document XzboDY40LYEv90439o45okJQ4

FILE NAME: Talc (TALC) DATE: 1960 Nov DOC#: TALC104 DOCUMENT DESCRIPTION: Medical Journal Article - Problem Areas in Pneumoconiosis Reprinted from the Archives of Environmental Health November 1960, Vol. 5, pp. 428-437 Copyright 1960, by American Medical Association Problem Areas in Pneumoconiosis MORRIS KLEINFELD, M.D., and JACQUELINE MESSITE, M.D., New York The residual problems relating to the pneumoconioses are numerous. In essence, however, these can be grouped into 3 main areas, namely, (1) the establishment of causal relationship; (2) the evaluation of the degree of disability, and (3) the medico legal factors. These 3 categories are inter dependent and interrelated. The Establishment of Causal Relationship The establishment of causal relationship in any one case requires a knowledge of the occupational chest disease as well as precise information concerning the industrial envi ronment wherein the alleged exposure has occurred. It is in the latter area that the practicing physician is often handicapped, since he does not usually have sufficient information about the industrial environ ment. This is readily understandable, for rarely does he have the opportunity to visit the work site, acquaint himself with the industrial processes, the materials used, and the degree of protection afforded. Further more, evaluation of the work environment often cannot be accomplished by mere in spection but requires detailed chemical and physical analysis of the air-borne dust and parent compounds to which the worker is exposed. Only infrequently does the physi cian avail himself of a state industrial health agency to obtain assistance in this area. There are numerous instances which can be utilized to demonstrate how knowledge of both the industrial environment and the occupational chest disease in question is important in determining causality. The following examples will serve to illustrate the importance of knowing some of the factors relating to the industrial environ ment. 1. Significance of Particle Size of the Dust. A group of workers were exposed to a parting compound which contained 50% free silica. The dust counts taken of the general air and at the breathing zone of the workers at the various operations con sistently disclosed air concentrations well above the maximum allowable limit of 5 mppcf. The average duration of exposure of these workers was 12 years. However, in spite of the high exposure, there were only minimal respiratory complaints. Clinical examination of these workers did not reveal any notable abnormalities referable to the cardiorespiratory system. Fig. 1.--Posteroanterior view of chest of Patient 1, a silica brick molder who had 18 years of fielPdSUre The roentgenogram shows clear lung Received for publication Aug. 10, 1960, Director, Division of Industrial Hygiene, New York State Labor Department (Dr. Kleinfeld). Chief, Medical Section, Division of Industrial H y giene, New York State Labor Department (Dr. Messite). ` 64/428 PNEUMOCONIOSIS--PROBLEM A REAS No significant incidence of positive x-ray plaints and x-ray evidence of pulmonary findings for silicosis was obtained. talcosis as compared with the other. The Figure 1 is a chest roentgenogram which only discernible difference was in the phys is representative of the group. The prin ical characteristic of the talc dust. In the cipal operation of this worker (Patient 1) plant where the workers' exposure was to was that of a molder for 18 years. He was the fibrous rather than the granular variety asymptomatic and no abnormal clinical find of talc, a significantly higher incidence of ings were observed. dyspnea, productive cough, and chest pain The absence of clinical and roentgeno- occurred. Similarly, the x-ray findings of graphic evidence of silicosis, in the light of the chest were more abnormal in this group. a persistent exposure to excessive concen The reason why the fibrous variety is more trations of free silica, required further anal pathogenic is not readily apparent. Figure 2 ysis of the dust, particularly for particle is the chest roentgenogram of Patient 2, a size. Of significance, the size of the silica talc miller who was exposed to a fibrous particles was predominantly above 10/r variety of dust for 32 years and shows a which is beyond respirable range. The lack diffuse fibronodular infiltration bilaterally. of consistency between the environmental This is in contrast to Figure 3, which is and medical data is, therefore, explained the chest roentgenogram of Patient 3, a by the latter observation. talc miller who had been exposed to a This study emphasizes what is not often granular variety of talc for 33 years, and appreciated, namely, that exposure to a shows only increased bronchovesicular known toxic dust does not necessarily result markings. Figure 4 shows a sample of the in the development of a disabling pneumo fibrous variety of talc dust and this is coniosis. significantly different from the granular 2. Importance of the Physical Character type as seen in Figure 5. istic of the Dust.--Despite similar degrees 3. The Importance of Knowing the De of exposure to talc dust in two different mills, the workers associated with one plant showed appreciably more respiratory com tails of the Worker's Job.--Not infrequent ly the physician, while obtaining an occupational history, is misled by his pa tient's job title. For example, a worker Fig. 2 --Posteroanterior view of chest of Patient 2, a miller of tremolite talc for 32 years. Note diffuse fibronodular infiltrations in middle and lower lung fields bilaterally. The left cardiac border is partially obscured by the infiltration. may have a designated title as a "plater," which would imply that he works with plat ing solutions and is exposed to various Fig. 3.--Posteroanterior view of chest of Patient 3, a miller of granular talc for 33 years. Increased bronchovesicular markings are seen. Kleinfeld-- Messite 65/429 ARCH IVES OF ENVIRONM ENTAL H EALTH Fig. 4.--Photomicrograph of crushed talc ore showing square and oblong particles and spicules characteristic of tremolite talc; X 72S solvents and metals required for platingoperations. However, he may also do some polishing with a sandstone wheel and thus be exposed to silica dust. To avoid such pitfalls, the physician should make inquiry as to the exact details of his patient's work. At times it is rewarding to know also what other operations are carried on in the vicin ity of the patient's area. It is possible that a worker may be exposed to dust from an adjacent operation even though he is not performing it. The following case illustrates the need for knowing the details of a worker's job. Patient 4, a 69-year-old white man, was hos pitalized because of shortness of breath, wheezing, and pain in the right side of his shoulder of 5 days' duration. His past history revealed that he had been suffering from chronic lung disease for about 15 years and for the past 6 years had been troubled by asthmatic attacks. In addition he had had a weight loss of about 30 lb. during the 3 months prior to admission. Occupational history disclosed that the patient had been retired for 6 years, but prior to this 66/430 Fig. 5.--Photomicrograph of crushed talc ore showing aggregates of granular or scaly particles; X 725. he was a steam fitter, a job requiring not only his building, maintaining, and repairing furnaces, but also the cleaning of them. He performed this dusty job often without taking any protective measures, such as use of a mouth respirator. Clinical examination showed a thin elderly white man who was cyanotic, dyspneic, and somewhat disoriented. The eyes reacted to light and ac commodation. The chest was emphysematous, and the patient was using his accessory respiratory muscles during breathing. The lungs were hyper resonant. There were dry rales scattered through out both lung fields. The heart was not enlarged, and the rhythm was regular. There was a systolic murmur Grade 1 at the apex. The blood pressure was 135/75. There were no abnormal abdominal findings. The extremities did not show any atrophy or wasting. The nail beds were cyanotic. The peri pheral pulses were felt. The pulse was 108 and regular, the respirations 28, and temperature 99.4 F. Laboratory data: Urinalysis showed a 1 + pro teinuria and occasional white cells in the sediment. The hemoglobin was 12.4 gm. % ; white blood count 9,500 cells/cmm, with a normal differential Sedimentation rate was 26 mm, BUN 12 mg/100 cc. ; COa 22.6 mEq ; sodium 139 ; potassium 4, and chlorides 89 mEq. Sputum culture was negative. Vo/. 5, N o v , 1960 PNEUMOCONI0 SIS--PROBLEM AREAS Fig. 6.--Posteroanterior view of chest of Patient 4, a maintainer and cleaner of furnaces for ap proximately 20 years. A mottled infiltrate is seen in the upper left upper lobe. The lower lung fields are emphysematous and a patchy area of pneumonia. Chest roentgenograms taken on admission showed a displacement of the mediastinal structures to the right with a considerable amount of hazy mottled infiltrate in the left upper lobe having both a reticular and a miliary pattern. The lower lung fields were emphysematous, and there was a patch of infiltrate in the left base. The appearance sug gested a probable pneumoconiosis associated with a patchy area of pneumonia (Fig. 6). The patient was given oxygen, bronchodilators, and antibiotics, and showed some improvement ini tially. However, his mental state gradually de teriorated and he became completely disoriented. Three weeks after admission, he suddenly died. An autopsy was performed and showed prima rily an extensive pulmonary anthracosis, broncho pneumonia bilaterally, and pulmonary emphysema predominantly right. The extensive anthracosis seen in this patient's lung is probably due to his chronic exposure to carbonaceous material while cleaning the fuel burn ers, which he had done for at least 20 years. Similar cases have been reported by others, par ticularly among superintendents who did extensive cleaning of coal stoves without using proper pro tective measures The following will illustrate the impor tance of having a broad knowledge of the occupational dust diseases in the determina tion of causal relationship. This implies not only a knowledge of the clinical and differential diagnostic aspects, but also of the epidemiology of the disease as is indi cated by the following case history. 1. The Importance of Knowing the Epi demiology of the Industrial Dust Diseases.-- The following case demonstrates the im portance of knowing the epidemiology of the disease. Patient 5, a 35-year-old Negro woman, was found to have, on a routine chest roentgenogram taken at the local health clinic, an abnormal chest x-ray characterized by micronodules scattered bi laterally throughout both lungs. She was asymp tomatic, and her past medical history as well as systemic review was nonrevealing. Occupational history disclosed only one episode of dust exposure; this was at the age of 23, when she was employed for 13 months in a steel plant where she used a compressed air hammer to re move hot sand from cast iron. During this opera tion, she was exposed to heavy concentrations of dust for the first few months, after which time a water spray was instituted to suppress the dust. She disclosed also that she had lived for a period of 2Yi years about 6 miles from a beryllium plant where her husband was employed. During this period, her husband brought his contaminated clothes home for frequent washing. Physical examination showed a healthy-appearmg Negro woman, of good color. The physical examination did not show any abnormalities. Lab- Fig 7.--Posteroanterior view of chest of Patient 5, a Negro housewife, who had a nonoccupational exposure to beryllium from laundering con taminated work clothes. Micronodules are seen diffusely scattered bilaterally, as is compatible with berylliosis. illeirde i --iff rr/43i A R C H IV E S OF E N V IR O N M E N TA L H E A L T H oratory work-up, including histoplasmin, coccidioidin, tuberculin, and Kveim skin tests, peripheral blood study, total protein determination, and blood cell count, showed no abnormalities. The chest roentgenogram showed micronodules diffusely scattered bilaterally. The heart size and pulmonary artery segments were normal. The costophrenic angles were diminished (Fig. 7). The history and chest roentgenogram suggest that she most likely has berylliosis, which has been reported to have occurred from such type of exposure.1 The chest x-ray was compatible with berylliosis, although sarcoidosis cannot be en tirely excluded. 2. Similarity Between Occupational and N onoccupational Pulmonary Diseases.-- The following cases of pulmonary disease observed in a father and son illustrate the problems of differential diagnosis between Fig. 9.--Posteroanterior view of the chest of Patient 7, the 18-year-old son of the miner in Figure 8, showing similar findings He had a minimal talc exposure for two years. occupational and nonoccupational pulmo nary diseases. Patient 6, a 49-year-old white man, complained of a nonproductive cough of several years' dura tion, which had progressed only slightly. There were no other symptoms. Past history and sys temic review were noncontributory. The occupa tional history revealed that he had been a miner of granular type of talc for 19 years. He had no history of any other occupational dust exposure. pig. 8 --Posteroanterior view of chest of Patient 6, a miner of granular talc for 19 years. The roentgenogram shows diffuse micronodular and calcific densities distributed throughout both lung fields. It is compatible with a diagnosis of histoplasmosis, which is endemic in the area where this patient resides. Clinical examination revealed a well-developed, well-nourished man of good color. There were no abnormal physical findings. A chest roentgeno gram taken during a plant survey showed diffuse micronodular and calcific densities distributed throughout both lung fields (Fig. 8). Patient 7, 18 years of age was asymptomatic. His past history and systemic review were non revealing. Occupational history showed that he had been employed for 2 years in the same plant where his father worked, but was assigned to the insecticide department where the talc exposure was minimal. Physical examination showed no abnormal find ings. A chest x-ray taken during the same plant survey also showed minute calcifications and a few micronodular densities (Fig. 9). These two cases illustrate some of the problems in differential diagnosis between occupational and nonoccupational disease. Among the differential diagnoses to be con sidered are pulmonary talcosis, histoplasmo sis, and siderosis. In the father, who has had a potentially hazardous exposure to talc dust for 19 years, the practicing physi cian may entertain a diagnosis of pulmonary talcosis. However, the presence of a similar chest roentgenogram in the son, whose ex posure to talc was only minimal, makes such a diagnosis highly unlikely. Furthermore, the roentgenograms are somewhat atypical for pulmonary talcosis following exposure to the granular variety of talc. In the latter type of exposure one observes more of a hazy mottling and interstitial infiltration 68/432 Vol. 5, Nov., 1960 PNEUMOCONIOSIS--PROBLEM A R E A S with basilar involvement primarily. Since the area where these people reside is en demic for histoplasmosis, this would seem the more likely diagnosis in both of these workers. 3. The Significance of Knowing the In cubation Period of the Occupational Chest Diseases.--In 1938, a chest roentgenograph- ic study of 126 workers in 7 plants engaged m the manufacture of cleansing powders was performed by the Division of Industrial Hygiene in cooperation with the Division of Tuberculosis, New York State Depart ment of Health. The manufactured product contained, for the most part, a finely ground quartz compound, silex, and other siliceous materials of a slighter degree of toxicity as feldspar and volcanic ash. Although this was primarily a chest x-ray survey, all the workers were questioned as to previous occupational exposure to dust. The results showed that 18, or 14.3%, of the employees had roentgenographic find ings compatible with silicosis in all stages. Fig. 10.--Posteroanterior view of chest of a laborer (Patient 8) who had an industrial ex posure to a fine cleansing powder for 4 years Nodular infiltrations are seen widely distributed bilaterally. Of these, 4 had x-ray evidence of silicotuberculosis. The mean age of the positive cases and the mean duration of exposure were 40 and 9.8 years respectively. Of particular interest is the fact that 3 of the workers with roentgenographic evidence of silicosis had been employed in this industry for 4 years or less and had had no previous occupational exposure to silica and other dust. The mean age of these 3 cases was to cleansing powders containing 96% silica and 4% oxalic acid. Although the latter author alludes to the role of oxalic acid as responsible for the rapid development of silicosis, it is noteworthy that this acid was not an ingredient of the cleansing powders manufactured by the plants surveyed by this Division. It is worth stressing that a diagnosis of pneumoconiosis should not be excluded from the differential diagnosis 30 years. Figure 10 is the chest roentgeno simply on the basis of a relatively short gram of a 30-year-old laborer (Patient 8) exposure to a known fibrogenic dust. who was exposed to this dust for 4 years. The roentgenographic picture shows nodu lar infiltrations throughout both lung fields. This study serves to illustrate the fact that excessive exposure to a highly siliceous material of inhalable particle size can pro duce roentgenographic evidence of silicosis in a shorter period of time than the 10 or more years usually required. This has been corroborated by other investigators. For example, Strutek2 describes roentgeno graphic manifestations of silicosis in 3 workers exposed for a period of 1% years Evaluation of Degree of Disability Experts in the field recognize that the evaluation of the degree of disability in workers with pneumoconiosis requires a de tailed analysis of their environmental ex posure, a complete medical and occupational history, clinical evaluation, appropriate roentgenograms, pulmonary function tests, and, in certain instances, a pathological ex amination of lung- tissue. U su ally none of these approaches by itself will suffice. It is generally agreed that there is no substitute for the clinical examination, but Kleinfeld--Messite 69/433 ARCH IVES OF ENVIRONM ENTAL H EALTH as a single parameter it has its limitations. It must be correlated with the environmen tal data, chest roentgenogram, and other appropriate tests to be of value both diag nostically and as a basis for evaluating disability. When tuberculosis develops in a silicotic person, one can say with certainty that he is completely disabled, even though this may be at variance with his clinical picture. The utilization of the chest roentgeno gram alone as a basis for disability evaluation is similarly unreliable. It is note worthy that Greenburg, who studied a group of rock drillers in New York State, reported that approximately one-fourth of the men whose chest x-rays showed ad vanced silicosis had no complaints. A sim ilar observation was noted in granite cutters.3 In contrast, a worker may be seriously disabled by persistent breathless ness and yet have little or no roentgenographic evidence of pulmonary disease. This has been particularly emphasized by British investigators.4 Such cases are often diag nosed as bronchitis and/or emphysema, although either diagnosis may be difficult to prove clinically. This lack of clinical and radiographic correlation has been seen especially in workers who have been em ployed for many years at a coal face or in iron and steel foundries. Hence, the ab sence of characteristic roentgenographic abnormalities should not exclude the asso ciation of a patient's complaints with his occupational exposure. If a worker mani fests respiratory impairment and gives a history of sustained exposure to a dust, one must consider seriously the causal relation ship of the industrial exposure to the pul monary dysfunction, even if the patient's chest x-ray reveals only minimal changes. When nodular shadows are seen on the chest roentgenogram, it is appreciated that the size of the nodularity may bear no direct relationship to the `patient's pulmonary symptoms of his degree of disability, ex cept in rare instances where single or con glomerate masses are critically located and 70/434 produce obstruction of a bronchus resulting in respiratory symptoms. In general, it is the dispersion of the nodularity which bears a closer relationship to the patient's clinical picture. For example, micronodules, if dis persed throughout the lung parenchyma, are more likely to produce respiratory symp toms than conglomerate masses localized peripherally. The latter is illustrated by the following case. Patient 9, a 59-year-old man, was hospitalized because of a painful right knee, of one week's duration. Three days before admission, the knee became hot and swollen. There was no history of recent trauma. At the age of 15, he developed an osteomyelitis of the lower third of the right femur, which healed after several months. He has been in excellent health since. Surgical his tory, review of systems, and family history were noncontributory. The occupational history re vealed that he had been a street laborer for 27 years, digging trenches with a pick and shovel. Occasionally, he operated a pneumatic drill and hammer. Physical examination showed a well-developed, well-nourished man of good color. With the ex ception of minimal crepitus of the right knee and a depression along the lower portion of the right femur (the site of the old osteomyelitis), the physical findings were essentially negative. Fig. 11.--Posteroanterior view of the chest of Patient 9, a street laborer who dug trenches and intermittently used a pneumatic drill for 27 years. Vol. 5, Nov., 1960 PNEUMOCONIOSIS-PROBLEM AREAS Routine blood chemistry studies, peripheral blood count, and urinalysis were normal. Chest x-rays revealed a normal cardiac con figuration, with multiple shadows of varying sizes in both lung fields (Fig. 11). The radio gram suggested metastatic pulmonary carcinoma. Urologic studies, including retrograde pyelography, were normal. ' The pain and swelling in the right knee subsided with bed rest, and the patient returned to his former job completely asymptomatic. A chest roentgenogram taken 6 months later showed no change from the film, and the patient appeared to enjoy excellent health. The clinical impression of metastatic pul monary carcinoma, strongly entertained during the patient's hospital course, ap peared less likely in view of his lack of changes in (1) clinical picture after nine months of observation, (2) serial chest roentgenograms, (3) blood picture, includ ing blood counts and chemistries, and' (4) gastrointestinal and genitourinary x-ray series. A more probable diagnosis was pneumoconiosis causally related to his occu pation. It is of a particular interest in this case that the relatively large circumscribed masses distributed in the lung fields, espe cially peripherally, were not accompanied by any clinical abnormalities. There is a growing belief that the pul monary function approach provides the best yardstick for evaluating disability. There is a great need to utilize a group of pulmo nary function tests, particularly maximum breathing capacity, timed vital capacity, pul monary ventilation at rest and after exer cise, and oxygen diffusion measurements across pulmonary capillary bed to evaluate alterations in pulmonary physiology. None theless, these tests may not reflect the pa tient's clinical status or his ability to perform at his job. This is particularly true in the early stages of pulmonary dust disease. It has been repeatedly shown that it is often impossible to demonstrate subnormal pulmonary function in men who have extensive simple discrete nodular sili cosis, and not infrequently persons who have extensive conglomerate silicosis show only a moderate deviation from their normal respiratory capacity. As some have in t i /einfcld--M essi te dicated, it is more important to obtain repeated pulmonary measurements in the same individual and have his initial data serve as a control for subsequent compari son. This is particularly of value for such tests as maximum breathing capacity where the range of normal is very wide. Similar widespread values were observed by Wright in a study of maximum ability for sustained physical energy. The latter study revealed a variation of 25% above and below the mean maximum capacity for exercise as measured in a group of normal persons.5 In essence, one must conclude that neither the conventional methods of examination nor the more refined methods of pulmonary function determination can serve by them selves or collectively as a consistent reliable yardstick for the evaluation of degree of disability. This is particularly true for pur poses of workmen's compensation where the evaluation of disability is usually based up on the worker's inability to earn full wages in the work at which he was last employed or at which he was exposed to the hazard responsible for the disease rather than a physiologic basis of dysfunction. The phy sician must therefore be familiar with other factors which are important in evaluating his patient's disability, such as the require ments of the job, the worker's attitude toward his work, his intelligence and neuro muscular coordination. A worker's over-all capacity for his particular job is not predicated purely on his physical ability but in addition is dependent upon his psy chological attitudes, such as incentive, his mental capacity, and his neuromuscular function to develop a skill and efficiency for a particular operation. These factors in many circumstances may compensate for the physiologic incapacity. The physician should, whenever possible, obtain an intimate knowledge of the work er's job requirements. Unfortunately, the practicing physician often lacks such infor mation and he is thus handicapped in his appraisal of the worker's ability to perform at a specific job. Since the physician is . 71/435 A R C H IV E S OF E N V IR O N M E N TA L H EALTH usually placed in a position of determining whether or not a person is physically com petent to carry on a particular job, it is evident that he must obtain complete infor mation regarding all of these factors if he is to appraise the worker's disability with any degree of adequacy. Medicolegal Factors The previous discussions have been concerned primarily with medical consid erations in the diagnosis and disability evaluation of pneumoconiosis. However, the physician must also be aware of the legal technicalities in order to deal with problems of compensation in these diseases. Perhaps the greatest difficulties arise from those provisions in present workmen's com pensation laws which fail to recognize the medical facts. These include the legal con cept of disability, the limitation of compen sation to total disability, and the time limits for filing claims. Legal Concept of Disability.--Disability, in 20 states that define the term in their workmen's compensation laws, is expressed either as inability to earn any wages in the employment where last employed, or inabil ity to perform any further work in the occupation in which the employee was en gaged, or inability to earn similar wages in other suitable employment. It is noteworthy that the legal concept of disability is based upon ability to per form work or earn wages rather than physiologic loss of function. As already mentioned, the ability to perform work is influenced by factors other than those which affect physiologic capacity. These include incentive, skill, and economic need. Perti nent to the latter, there have been cases in which medical consultants of workmen's compensation boards have recommended awards for medical total disability on the basis of clinical disability and significant dust exposure. Yet, because the compensa tion benefits for wage loss are insufficient to meet their needs, these workers prefer to remain at their jobs, thereby receiving no compensation except medical payments.6 It "2/436 is noteworthy that in cases of hearing loss, awards are being made on the basis of physiologic loss rather than on earning ca pacity. Limitation of Compensation to Total Dis ability --In 20 states, partial disability for pneumoconiosis is not compensable.7 How ever, before any adequate basis for compensation for partial disability in pneu moconiosis can be established, it is essential that the physiologic concept of disability be accepted and that practical and adequate criteria for the evaluation of such disability be developed and applied. Present-day tests of pulmonary function do not accurately assess the degree of dis ability. Bronchospirometry can establish the physiological integrity of individual portions of the lungs. However, it is diffi cult to perform, often unsatisfactory, and therefore impractical for the purpose of disability evaluation for compensation. At best, pulmonary function measurements pro vide only an estimate of the degree of dis ability in pneumoconiosis. Time Limit for Filing Claims.--Probably the most inequitable provision from the point of view of the physician is the time limitation which excludes claims not made within a legally specified interval after ex posure. About 18 of the state compensation laws specify such an interval, which varies from 1 year to 5 years.7 This is unreason able, particularly where compensation is limited to total disability. In New York State, for example, the law requires that a worker be totally disabled by pneumo coniosis. To obtain compensation, a person must file a claim within 2 years after he leaves the employment wherein his dust ex posure allegedly occurred. This application of the statute of limitation is inconsistent with the known natural history of the dis ease. Clinical and epidemiological studies clearly indicate that the fibrotic process, once initiated, may be progressive even m the absence of further exposure. Disability, therefore, may not appear until lory after the person has left the dust exposure. Vol 5 No: I960 PNEUMOCONIOSIS--PROBLEM A R E AS New York State, recognizing that some diseases may develop long after a worker has left a hazardous work area, has since 1947 excluded from the statute of limita tions claims filed for certain occupational diseases such as those due to arsenic, benzol, and ionizing radiation. However, only one pneumoconiotic agent, namely beryllium, has been listed in this group.8 It would be desirable that the time limitation be re moved in the cases of claims filed in connection with diseases due to other pneu moconiotic agents which produce progres sive pulmonary diseases. In essence, the solution to the medico legal problems in pneumoconiosis is depend ent to a large extent upon more extensive epidemiological studies of these diseases and the development of adequate and prac tical criteria for the evaluation of disability. It is through such pursuits that the necessary data on which to base strong arguments for equitable legislative provisions in compen sation for pneumoconiosis will be accumu lated. Summary and Conclusions Three major problem areas in pneumo coniosis are discussed; these include estab lishment of causal relationship, evaluation of the degree of disability, and medicolegal factors. In view of the similarities between occu pational and nonoccupational pulmonary diseases, the physician, in order to establish causality, must obtain detailed information of the industrial environment wherein the alleged dust exposure occurred. Frequently this requires, in addition to inspection of the work site, detailed chemical and physical analysis of the air-borne dust and parent compounds to which the worker has been exposed. Cases are cited to illustrate the importance of knowing such factors as the particle size and physical characteristics of the dust and the details of the worker's job. The establishment of a causal relation ship in any one chse of pneumoconiosis is also dependent on a complete knowledge of these diseases. Examples are given to dem onstrate how a knowledge of the epidemi ology, incubation period, and differential diagnosis of these diseases is essential in establishing causality. Neither the conventional methods of ex amination, i.e., clinical, roentgenographic or pathological, nor the more refined methods of pulmonary function determination can by themselves serve as a consistently reli able yardstick for disability evaluation in a case of pneumoconiosis. Until such time as more precise criteria for disability measure ment in these diseases are developed, the physician frequently must combine all of these approaches before arriving at a de cision. The legal concept of disability, namely, the inability to perform work or earn wages, further complicates the problem of evaluat ing disability. This is particularly true since the ability to perform work is influ enced by other factors, such as incentive, skill, and economic need, in addition to the physiologic capacity. The limitation of compensation to total disability and time limits for filing claims are additional factors which present prob lems to the practicing physician. A dis cussion of these factors is included. 80 Center St. REFERENCES 1. Eisenbud, M., et a l.: Non-Occupational Berylliosis, J. Indust. Hyg. & Toxicol 31 :282 (Sept.) 1949. 2. Strutek, J . : Silicosis in Workers Packing Cleansing Power (Accelerating Effect of Oxalic Acid?), Casop. lek. cesk. 87:343 (M arch) 1948. 3. Greenburg, L .: Some Aspects of the Problem of Silicosis, Indust. Bull. 15:195 (June) 1936. 4. Pemberton, J . : Chronic Bronchitis, Em physema, and Bronchial Spasm in Bituminous Coal Workers, A M.A. Arch. Indust. Health 13: 529 (June) 1956. 5. Wright, G. W .: Disability Evaluation in In dustrial Pulmonary Disease, J.A.M A. 141:1218 (Dec. 24) 1949. 6. Mayers, E .: Personal communication to the authors. 7. Analysis of Workmen's Compensation Laws, U.S. Chamber of Commerce, Washington, D.C., Jan., 1958. 8. New York Workmen's Compensation Law, Section 40. K leinf eld--M essite Printed and Published in the United Statee o f Am erica 73/437