Document 39roqX4qrMZVzjzQOLXk5BwD

56 1 'ecvty-first Congress--Xatiunal Safety Council TABLE 2 Average Dust Counts in Certain Dusty Trades Industry and Occupation Talc Mining and Milling: Jack-hammer drillers............. Packers ....................... Muckers ...................... Cnislamtai and cvlindcrnren___ Slate Finishing Mills; Floomivn .................... leaders ...................... Disc crusher ojicraturs............. Quartz Grinding Plant: Mill <i(frrat<irs................... Lalinrcrs ........................................ ........................... Parkers ............................................. Granite Quarrying and Finishing: I.ryncr drillers ...................... Jack-hamtnrr drillers ............. Dust exposure in millions of particles per cubic foot 83 Machine (tnctxmatic tool finishers. Attendant lalmr i indoor* ........ Anthracite Oal Mining: Miners and heljiers___ Attendant lalior ............ Pitcmtnmi* Coal Mining: Coal cutters and loaders .... Attendant latior ........... Marble Cutters ................... 1 ottm Cl'*th Manufacturing: Carders .......................................................................... Weavers and spinners........................ Silverware Manufacturing: Dustv trades ............... Xon-dustv tradi*< . 0 Average per cent of quartz in dust Sane None Sane 3 99 99 99 35 35 35 *7.5 1.5 1.5 1.2 1.2 Sane Sane Sane 1.7 1.7 1.7 evidence if ilicrc that appreciable j*crccmapei oi ordinary industrial dusts evtr fragment into thr*e minute sizes less than 0.5 microns in diameter? The best answer to this (Question would be data of actual measurement fit such dust. Un fortunately we have hut scant jnibhsheil data on the particle size frequency of dusts in the air of industrial establishments. In 192V Fehnel made some particle size measurements in connection with the dust study of hard rock drilling m New Y<rrk City. He reported the findings on three samples, which showed the dost which was less than 1 znicron hi size to vary' from 1 to 15 jktt cent. Most of the dust in these hard rock drilling oi*ratiuns was between 2 and 5 microns in size. Padham. in studying the dust hazard among sandstone W4irkcrs in Sydney. Aus tralia. measured some 76.000 particles of dust m the air of work places and found that 67 per cent oi these jiarticlcs were aliout 1 micron in size. In a panicle size Industrial Health Section study oi twenty-five samples of eleven different kinds of aerial industrial dusts made by the filar micrometer method at a magnification of 2.000 diameters, tlie speaker found that practically all of the dust was less than 5 microns in size. Only 2 per cent oi the particles were less than 05 microns. 21 per cent were less titan 1 micron, and the majority of the dust, 71 per cent, was found to he between I and 3 microns in diameter. From all of the evidence tlierefore, and in the absence of conclusive proof to the amtrarv, it is apparent tliat we need only be concerned whh those dust (articles lietwecn one-half and 5 microns in size, and from a practical standpoint the lower limit of particle size to he counted may well be taken at about 1 micron. Many methods have lieen devised and used for the purpose of determining the quantity of dust hi air. Suffice it to say that for the purpose of dust sampling in cither high or low* dust concentrations, the Grecnhurg-Smitlt impmger apjiaratus n*w finds universal favor. This instrument has been used by the United States Public Health Service in all of its dust studies during the past nine years and is also Iicing used by other workers m this field in this country and abroad. During tltc past nine years the writer has nude numerous investigations of dust Iiazard in many industrial establishments throughout the country. In Table 2, i summary is presented of the average dust content of the air in a few of these dusty industries. This table clearly shows that the highest dust c.\|iosure was in tltc talc mine*. slate finishing mills, quartz grinding plant, coal mining and granite cutting industries. Owing to the high percentage of quartz present in the dust oi the quartz . grinding and granite cutting plants, as compared with the dust in the other indus tries listed in Table 2. quartz grinding and granite cutting are revealed to lie the mirit hazardous of the occupations .we have studied, 4 ^ --------------------- - Clinicaf ana Statistical Aspects of Silicosis By ALBERT E. RUSSELL. M. D,, F. A. C. P. Surgeon, XJ. S. Public Health Service; Surgeon, U. S. Bureau of Mines, Washington, D. C. It would be difficult to estimate with any degree of accuracy the numlier oi (tropic hi the United States who are engaged in dusty trades. It is evident, however, that more jieoplc are exposed to dust, which constitutes the greatest single industrial haz ard. than is generally supposed. Certain dusts contain poisonous elements, such as lead, arsenic, mercury, etc- which give rise to general conditions resulting from their absorption. This pajier however will deal only with those dusts which arc known to be direct factors in the production of pulmonary diseases. Economic Aspects of Silicosis Tltc economic problem presented by silicosis is tremendous. Tltc suffering and loss of life due to it cannot be adequately measured. In the gold mining area around Johannesburg, South Africa, during the jtcriod 1911 to 1929. more than 5.1 million dollars have been paid in compensation alone. Tlie costs of medical care, hospital ization, and legal proceedings further augment this enormous figure. Mines in Australia are reported to have been bankrupted by payment oi silicosis compensation. I know* of a company ht our own country which has claims amount ing to more than a million dollars for disability due to dust inhalation. There arc other plants in the East which will lie bankrupted if all the claims which are filed against them are allowed. In most of the industrial states the numlier of claims filed has greatly increased in recent years. It is clear that dust-prcvcntkm work, like any health-promoting activity, would (ay many times in money, good health, and efficient operation. Strangely enough, only during the past 25 years has dust reccivec much attention