OCCUPATIONAL DISEASES IN THE MINING INDUSTRY

S. C. HOTCHKISS

Assistant Surgeon, United States Public Health and Marine Hospital Service,

Special Investigator for the United States Bureau of Mines.

While the subject of occupational diseases in the mining industry is of great interest, I feel some hesitancy at this time in attempting to present an account of the investigations carried on by me in Colorado during the past summer. This is due to the fact that the studies have not as yet been completed nor the data collated or sufficiently digested to draw detailed conclusions. The investigations mentioned were undertaken and conducted through the joint cooperation of the United States Bureau of Mines and the United States Public Health and Marine Hospital Service. It is recognized by both bureaus that the health of miners and the sanitation of mines must of necessity have an important bearing on the economic aspects of mining and on the health of the country generally.

More or less interest in the question has been manifested in different sections of the country, as is evidenced by investigations and demonstrations of the presence of hookworm disease in the coal regions of West Virginia and in the gold mines of California, and by the suspicion, among agencies for the prevention of tuberculosis of the undue prevalence of affection of the lungs among miners, especially in the metalliferous mines. It is also known that, in certain sections at least, insanitary conditions prevail in mines; and the great loss of life that frequently occurs as a result of explosions, noxious gases, and the falling of rock, is a matter of common knowledge. In fact, it is becoming more and more apparent that the health of employes has an important bearing on the prosperity of the industries in which they are engaged. These reasons and the desire to protect the health of miners and to render their labor more effective led to the inauguration of the investigation.

In accordance with official orders, the past summer and fall were occupied by me in investigations in Colorado of conditions of

the mining industry affecting the public health, particularly with reference to the prevalence and causes of diseases of the lungs among miners. A brief portion of this time was devoted to studies of the coal mining industry in that state, and twenty-five coal mining camps and the underground workings of seven mines were inspected. Other officers, however, had previously undertaken investigations of the coal mines of West Virginia, and it was the original intention to confine the work in Colorado to a sanitary survey of the metalliferous mines.

The work in relation to metalliferous mines included inspections in eight of the principal mining districts, examinations of the underground workings of twenty-six mines, and examinations of the chests of four hundred and seventy miners and mill men. A large number of mine operators, foremen, miners, physicians and others connected with the industry were interviewed. A study was made of existing statistics collected by state and local authorities, and studies were undertaken to determine the extent of migration of miners, especially of those affected with pulmonary diseases.

Consideration of the subject of occupational diseases can not confine itself to diseases distinctly attributable to the hazards of the occupation. It must of necessity include a much broader field. That is, in addition to the dangers while actually at work, social and economic conditions have an important bearing.

Among the occupations of importance from a sanitary standpoint are those involving exposure to air vitiated by respiration, to irritating and poisonous gases and fumes, to irritating and poisonous dust, to infective matter in dust, to offensive gases and vapors, to extremes of temperature, moisture and pressure, to poverty, and to filth. It was attempted to collect data to determine the extent to which these conditions prevailed in the metalliferous mines inspected, and their bearing on the incidence of lung diseases.

It is well known that persons engaged in certain dusty occupations are more subject to diseases of the lungs than are persons in less dusty occupations. Hard, insoluble dust particles, having sharp edges and corners, are believed to be more injurious to the lung tissue than are particles which are comparatively free from these sharp points. Coal dust is of this latter type, while the dust of many metalliferous mines conforms to the former type. Comparisons

may therefore be made of the two industries. It has been found in England and Wales that the percentage of mortality from discases of the respiratory organs was only about four-fifths as high among coal miners as among all males, while the percentage mortality from these diseases among Cornish metal miners was exactly three and one-half times as high as that of coal miners. In the districts of Colorado that were investigated the percentage mortality from lung diseases, during the years 1902 to 1910 inclusive, was more than four times as high among metal miners as it was among coal miners. Studies are being made of the mortality from these diseases among miners as compared with that of the general adult population of these districts.

Metal mining is classed as one of the dusty occupations, and we would therefore naturally expect to find a high prevalence of lung affections among the persons engaged in it. Other factors than dust, however, must be considered. The metal miner works in an atmosphere which frequently contains noxious and poisonous gases; he sometimes works in ores containing chemicals which may cause toxic effects; and, under the conditions which prevail in all but a few mines in Colorado, he is frequently exposed to sudden and wide variations in temperature. Other conditions, moreover, incident to the life of the miner, tend to lower resistance and may thus predispose to lung diseases.

The principal occupational diseases of miners which will be discussed at this time, are:

I. Those induced by the inhalation of dust, known as silicosis among metal miners and as anthrocosis among coal miners.

2. Those induced by noxious and poisonous gases, the symptoms of which depend on the kind of gas inhaled.

3. Those diseases or intoxications caused by poisonous metals contained in the ores being mined, lead poisoning being the principal one.

The two latter groups, by lowering resistance, may be predisposing causes to miners' phthisis or to silicosis among metal miners.

It is difficult to ascertain the actual amount of miners' phthisis. Frequently miners will not submit to a physical examination; and studies of the death records give incorrect results, since men affected with miners' phthisis frequently die from accident, pneumonia, or

some other cause, and no mention of the miners' phthisis is contained in the death certificate. Yet I found in one district in Colorado that this preventable disease was recorded as the chief or contributory cause of 30 per cent of the deaths which had occurred among miners there during the past nine years, while the mortality from all respiratory diseases was 56 per cent of the total mortality reported among these miners. Nor does this tell the whole story, for it is customary for some of the miners, when they become short of breath, to leave the mines and go to a lower altitude. If the deaths among these men were added to the figures just given, the mortality from lung diseases would be increased very appreciably. In this same district, it was found that the death rate from lung diseases contracted in Colorado was more than three times as high among miners as among the rest of the adult population.

Miners' phthisis is very prevalent among metal miners in various foreign countries, especially among Cornish miners in England and among the miners on the Rand in South Africa, where it is stated that 25 per cent of the European miners suffer from phthisis in the various stages of the disease.

Mention must be made of tuberculosis and pneumonia among miners. While these may not be classed as distinctively occupational diseases, they are undoubtedly responsible for a large number of deaths among metal miners. It is not difficult to see why this should be so when one considers the conditions under which the miner carries on his occupation, and it is quite probable that a man suffering from miners' phthisis is more liable to contract either of these diseases, especially the former, than a man not so affected. An important and rather frequent cause of death among miners appears to be poisonous gases formed by the imperfect detonation of high explosives. My attention was especially called to this while in the Cripple Creek district, where a man died of oedema of the lungs, probably as a result of exposure to powder smoke. The symptoms were those of acute poisoning by nitrogen compounds, and the diagnosis was confirmed by post-mortem examination. In this same district report was received of twenty similar cases within a period of ten years, all but two of them fatal. Similar cases were also reported to me as having occurred in the Leadville district, and there is record of nine fatalities attributed to the effects of the in

halation of powder smoke, out of a total of thirteen men who were exposed to the fumes while working in the Gunnison Tunnel.

Men working in mines are frequently exposed to powder smoke. In some mines shots may be fired at any time, though the great majority are fired at the end of the shift. Some of the mines visited work three shifts in twenty-four hours; others, which work only two shifts, send the second down within an hour after the first comes out; in both cases men go into the mines while the atmosphere contains considerable powder smoke. There is thus abundant opportunity for exposure to whatever deleterious influences such gases may exert

Although it is stated by some writers not to occur, mention must be made of lead poisoning among miners of lead ores. Reports were received by me of cases of lead poisoning in practically every lead mining district visited. In Leadville records were available of thirty-nine diagnoses of lead poisoning among miners treated at St. Vincent's Hospital during the past four years. Physicians in other mining camps spoke of lead poisoning as of rather common occurrence among miners. And a number of the men examined by me, who had miners' phthisis or ill health from other causes, attributed its beginning to an attack or to attacks of lead poisoning which they had had some years previous, and stated that their health had not been as good since they were "leaded". It seems probable, therefore, that lead poisoning does occur among lead miners in Colorado.

There is another class of diseases and infections to which miners are especially subjected where the temperature and soil conditions are favorable for their development. I must refer briefly to the general class of soil-pollution diseases. Under this term may be included all those infections which spread in and from soil which has been polluted by human discharges, for instance, typhoid fever, the dysenteries, Cochin China diarrhea, hookworm disease, etc. There are perhaps no diseases that are theoretically so easily preventable as these, and the most important single factor in preventing them is a safe disposal of excrement. Other things being equal, these maladies will spread under poor sanitary conditions, either in the mines or in the camps, and they will be inhibited directly in proportion to the care taken in safe-guarding the disposal of excrement.