Notes on pneumoconiosis

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THE T R A N S A T L A N T I C

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the proverb, " A fool can ask more questions in an hour than a wise man By Patrick Heffernan, M.D. can answer in a lifetime." It was a matter of regret to several THE great Canadian "Pre-cambrian Shield," of granite and gneiss, with members of the various medical groups inclusions of even older quartzite, later travelling to the British Medical Assogold-bearing granites, and pockets of ciation Meeting at Winnipeg that no time was available to pay a visit to the ice-borne conglomerate, covers " 9 5 per cent. of Quebec, 80 per cent. of great asbestos mines of Thettord, near Ontario, three-quarters of Manitoba, Quebec, which supply 85 per cent. of The mineral one-half of Saskatchewan, a small the world's asbestos. portion of Alberta, and a large slice comes from the chrysotile deposits of of the North-West Territories" [1]. the Appalachian region o~ Southern It constitutes an enormous reservoir Quebec. Specimens exhibited in the of silica rock, and within its area are Museum of the Royal York Hotel, mined gold, silver, nickel, copper, lead, Toronto, showed veins of fibrous ehrysoarsenic and zinc. The works already tile embedded in what appeared to be in existence, however, are probaby only grey granitic rock. If a definite dustan earnest or foreshadow of the future risk is attached to the getting of this developments of the mineral wealth of mineral, one could not help wondering this region. It is not to be wondered how much of that risk was attributable at, therefore, that the " d u s t - r i s k " run to the surrounding rock, and how much by the workmen employed in the various to the asbestos fibres. At the present industries based upon this geological time a commission is sitting in New formation should have received the York on the question of the dust-risk in anxious attention of the public health asbestos workers, and this report will be authorities, and, as we shall see later, published in due course. The investia great deal of research has been, and is gations which have been made appear being, devoted to elucidating the prob- to have followed closely those made a~ lems involved, and legislation, based home. At first, as with us, the "asbestos upon the results of this research work, bodies "'were considered to be fungoid has already been passed and imple- growths. According to one observer, mented by the Government of Ontario fibrosis was noted in workers dealing and of the ,other provinces concerned. with asbestos containing iron, while The information on which these notes those working with asbestos free from iron were not affected. are based was supplied by Dr. G . C . SILICOSIS IN CANADA. Brink, Dr. A. R. Riddell, and Mr. H. E. Rothwell of the Provincial Department The main dust-risks occur in gold minof Health, Ontario, as far as they deal ing in the Porcupine and Kirkland Lake with Canada, and by Dr. A. S. Lanza, area; in quarrying and dressing black, of the Metropolitan Life Insurance Co., grey and red granite; in cutlery-grindof New York, and Dr. Jacob A. ing,. sand-blasting, cobalt and nickel Goldberg of the New York Tuberculosis mining; in quarrying materials for ferroand Health Association (both members silicon and artificial abrasives; in iron of the Silicosis Committee of the last- and tile moulding, sand-paper making mentioned Association), as far as New and agate grinding. Much of the York is concerned. I take this oppor- " s a n d " for the sand-paper is crushed tunity to tender to these gentlemen the sandstone rock. In estimating these very grateful thanks of our party for the risks in Canada, much reliance has been willingness with which they placed the placed upon post-mortem examinations, results of their work and experience at and upon analysis of the silica content~ our disposal, and for the patience and of the ash of lungs of deceased workers good humour with which they bore employed in various industries, as comwith my inquisitiveness. One recalls pared with the lungs of ordinary city

Notes oa

Pneumoconiosis.

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and country dwellers. A report on this work will be published shortly, and will, I venture to say, be of very great value. Investigations are also being made on the blood-changes, if any, and on the excretion of silica in the urine. It was interesting to hear that Dr. Belt, of the pathological department, University of Toronto, when examining sections of silicotic lungs with the aid of Nicols prisms, found that sections through the fibrotic nodules showed no quartz particles towards the centre of the nodule, but numerous quartz particles towards the periphery, from which it was inferred that the particles towards the centre of the nodule had gone into solution. The free silica content of the combined quartz and country rock worked al the Porcupine mine was about 50 per cent., at Kirkland Lake 9.5 per cent. to 35 per cent., oi that of the silver and cobalt area 5 per cent. to 10 per cent., of the Sudbury nickel field 10 per cent. to 20 per cent., of Bari granite 64 per cent. to 80 per cent. The gold bearing quartz veins were, as in South Africa, practically pure silica. As regards cutlery and implement grinding, Dr. Brink does not consider that the dustrisk is entirely eliminated by the use of emery or corundum wheels. The substance most commonly used now is " Alundum," i.e., fused alumina. He considers that the skiagraphie picture in granite workers is different from that in gold miners. The latter tend to show the true nodular picture evenly distributed throughout the lung fields, while in the granite workers, although there is evidence of the formation of nodules, the fibrosis is more apt to pick out separate areas, and give massive shadows. The average length of time for the development of silicosis (in the cases in which it develops) is in the Porcupine area nine to twelve years. The shortest period during which silicosis developed from a radiographically clear chest to a radiographically primary stage of silicosis was nine months, in a man with a total exposure of two years and nine months. Sputum examinations are always made when sputum is available, and if negative by ordinary methods, guinea-pig inoculation is used. Contrary to the South African experience,

[ J a n u a r y , 1931

guinea-pigs often prove positive when the smear examinations have been negative. In this connection it should perhaps be noted that there appears to be, in some American centres, a reaction against guinea-pig inoculation as a test of tuberculosis, in favour of cultural methods. COMPENSATION SCHEME.

Legislation passed in 1926 made silicosis a compensatable industrial disease, and a special medical beard of medical men actively engaged in antituberculosis and chest work was set up to deal with ik The South African classification of ante-primary, primary and secondary stages is adopted. No man is considered for compensation who has not worked in the mines for five years, or in quarrying and grinding for at least three years. Annual examinations are made by a medical man on the spot, specially appointed for the purpose, and if he considers a case warrants, it is referred to the medical board, the findings of which must be unanimous. All persons joining the mining industry are examined before admission by the appointed medical officer. A physical examination and a " flat" skiagram of the chest are insisted upon; a " stereo," if considered necessary. If passed as fit, the medical officer issues a certificate to the workman. This certificate holds good for a year and may be taken by the worker to any mining camp. Granite workers, grinders and sand-blasters, although compensable, are not examined on joining the industries. Moulders are not compensable. After joining, all workers are examined annually, stereoradiography being used as a routine. The radiography is of a high order of excellence, and a stereo-picture of silicosis - - a fine snowstorm within a transparent barrel--is not easily forgotten. Dr. Brink uses in his travelling tuberculosis clinics a simple and inexpensive portable X-ray outfit which takes excellent slereo-skiagrams. The cassettes are changed and the tube shifted by h a n d - the essential appliance being a tubular frame holding the cassette--over which the standing patient folds his arms. A minimum distance of four feet between

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PNEUMOCONIOSIS

tube and film is insisted upon, but most Canadian chest radiography is done at a longer distance. The tube-shift has to be varied according to the distance, according to the laws of optics. It is recognised that tuberculosis and other lung conditions may simulate silicosis radiographically, and symptoms and physical signs are given due consideration. At the initial examination, tuberculosis, and any other disease of the chest which would predispose to silicosis, must be excluded. Strangely enough, no importance is attached to naso-pharyngeal obstruction, and Dr. Brink is of opinion that mouth-breathers run no greater risk than nasal-breathers. Vital capacity is estimated by measuring chest expansion. In this regard, inquiries were made in Toronto, New York, and at the Medical Exhibition at Winnipeg regarding instruments for measuring vital capacity. The only instrument actually on exhibit at Winnipeg was the " Flarimeter " w h i c h measures both vital capacity and cardiac competency. I t is used by the medical examiners of the Prudential Assurance Company of the United States in examining the clients of the Company. A somewhat similar technique has been elaborated by Dr. Harold M. Frost, Assistant Medical Director, New England Mutual Life Insurance Company, who uses a " T y c o s " vacuum pressure gauge and " T y c o s " spirometer. It is, perhaps, characteristic of the progressive spirit of the great Life Insurance Corporations of the New World that technique for the quantitative assessment of circulatory and respiratory fitness should be developed by them. As we shall see later, much of the American work on silicosis has been done at the Industrial Hygiene Laboratory of the Metropolitan Life Insurance Company, and the assistance given to tuberculosis workers by the Sun Life Insurance Company of Canada needs no publicity from the writer. One does not seem to hear of similar activities on the part of our Insurance Companies or Approved Societies. The work of Professor Georges Dreyer, in this country, on the assessment of physical fitness, is, however, well known. Dreyer uses the Boullite spirometer.

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PREVENTION OF SILICOSIS. The most striking step taken in this direction is the adoption of the " B u l m e r Air M a s k " by the Government of Ontario, which has patented the appliance. When a supply of compressed air is available this appliance is considered of great value; indeed, some consider that it has solved the problem of dust-risk in the mining industry. Dr. Lanz~ in New York was as enthusiastic about the appliance as Drs. Brink and Riddell at Toronto. Workmen use it readily and declare that they feel much fresher at the end of a work-shift than when without it. SILICOSIS IN THE UNITED STATES.

" M a n h a t t a n schist, which covers most of the Island of Manhattan, is a complex, highly variable micaceous schist which in many places is very massive and rich in quartz . . . . Samples taken by Fehnel from eight localities where excavation work was being done showed a total silica content varying from 56 per cent. to 94 per cent. and a free silica content of from less than 1 per cent. to 84 per cent." [2]. A study by the silicosis committee of the New York Tuberculosis and Health Association and the De L a m a r Institute of Public Health of Columbia University, published on February 7, 190.9, showed that of the 208 rock-drillers, blasters and excavators employed in New York City, who were examined, evidence of silicosis was found in 118 or 57 per cent. Of these only 7 per cent. or 3 per cent. s h o w e d " what were believed to be definite or suspected active tuberculosis lesions. . Sputum was obtained in only one oi the cases, and was negative." The death certificates of the rock-drillers for whom the Tunnel and Subway Construction and Industrial Union paid death benefits over the previous three years showed, however, that out of a total of 21 deaths, 15 were from pulmonary diseases, eight being pulmonary, tuberculosis [2]. There is no special compensation scheme for silicosis in the United States. Five States which have an all-inclusive occupational disease act, compensate for disablement due to silicosis, and one gathersthat the work-

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ing men employed in industries with a silica dust-risk in other States would prefer the extension of this measure, rather than a special silicosis scheme such as exists in Great Britain, Canada, South Africa, Australia and New Zealand. The New York drillers, blasters and excavators earn high wages - - 6 to 8 or 10 dollars a d a y - - a n d appear loth to have their occupation supervised or interfered with, preferring to carry their own risk. Dr. A. S. Lanza showed, at New York, some skiagrams of chests illustrating pulmonary aspergillosis, a somewh~t remote dust-risk run by men working threshing machines in the h~iddm Western States. The films resembled those of miliary tuberculosis which had undergone calcification rather than those of silicosis, the outlines of the granulations were much harder and more defined, and the opacity of the nodules more complete. Two papers were read at Winnipeg which were of great interest from the point of view of pneumoconiosis--one by Professor Lyle Cummins, the other by Dr. J. Harvey Pirrie of Johannesburg. As both will doubtless be published elsewhere, it is perhaps permissible to say that Dr. Lyle Cummins d e a l t with coal-miners' lung and the effect thereon of exposure to other dusts than coal-dust; while Dr. Harvey Pirrie, in dealing with the pathology of tuberculosis in African Natives, brought out the fact that while young South African Natives had little resistance to the disease, and usually developed a rapidly fatal acute form of preliminary tuberculosis, with early generalisation, and with no evidence of fibrosis, the presence of some silicosis in addition had the effect of converting the disease into a more chronic fibrotic form. One heard mentioned the work of Dr. Garner of Saranac, regarding the influence of silica on the virulence of tubercle bacilli, but Dr. Garner was in South Africa. Our experiences in Canada and the United States, brief though they were, strongly supported the principle laid down by Dr. Parsons at Toronto, that diseases of the chest--tuberculosis, bronchiectasis, post-pneumonic fibrosis, pneumoeoniosis, &c.--constitute a group

which must be taken as a whole, and should be dealt with at Chest Clinics by medical men specialising in diseases of the chest. Further subdivision of the work leads to narrow views, and errors in diagnosis. On the train between Winnipeg and Chicago we were supplied with iced "Chippewa w a t e r " from the famous springs at Chippewa Falls. Its analysis shows total solids 2"07 gr. per gallon, of which 0'42 grain is silica, which its " n a t u r a l " process of distillation does not apparently remove. The Bulmer air mask, designed by Dr. F. M. R. Bulmer, of the Ontario Department of Health, consists of a light, snugly fitting face-piece of cloth, partially covered with waterproof air-tight material, with a rubber tube about ~ in. in diameter leading into it. The tube is fastened to a webbing strap harness to prevent pull on the mask, and is connected to the compressed air line of the drill, &c., by a reducing valve. Any length of tubing may be used, to allow suitable radius of action. The mask, when in operation, is in an inflated condition. As long as enough air is supplied to keep it inflated the workman knows that protection is being provided. The pressure in the mask is always slightly higher than that of the environmental air. The weight of the mask with 18 in. of tube--i.e., the weight carried by the workman's head--is about 289 oz. I t costs, with webbing strap harness, two dollars. An oil and water filter can, if wished, be included in the air circuit at a cost of sixteen dollars. Masks or respirators which merely attempt to filter the dust.laden air surrounding the workman are now recognised to be useless or worse. The air breathed by the workman using the Bulmer mask is derived from the works air compressor, which must, therefore, be located in a dust-free atmosphere. REFERENCES. [i] CA~SELL, CHAS., B.Sc., LL.D. Mineral Wealth of Canada," from

"The " The

Book of Canada," published by the Canadian Medical Association, Toronto, 1930. [2] ROSS SMITH, ADELAIDE, M.D.

"Silicosis

among Rock Drillers, Blasters add Excavators in i%w York City," 5ou~'n. Indust. Hygiene, 1929, ii, 39.