Document 71XXQJ8y8VJjXXwNwqjDYo9mg

FILE NAME: Metropolitan Life (ML) DATE: 1935 DOC#: ML088 DOCUMENT DESCRIPTION: Book Excerpt - Industrial Medicine MAR-09-- 1995 13:23 S.S. HEALTH CTR. 617 356 4887 P.02/04 03/09/95 14:25 TX/RX NO.1272 P.002 144 INDUSTRIAL MEDICINE i which the engineer welcomes as an objective of cleanliness for which to strive. Some of these I figures are founded upon reliable data and some are frankly estimates, Legge and Duckering [104], [46] suggested I 0.5 mg. per cu.m. for lead dust which Russell and his colleagues [146] lowered to 0.15 mg. for litharge indicating that this figure might be scaled up or down with changes in the solubility S of the lead compound in serum. T he South African authorities, for their high quartz rock in the Witwatersrand gold mines, have gradually arrived at a figure of about 1 mg. U 'fi per cu.m. and silicosis, under their conditions, has not been eliminated (although greatly re _aJ'i; LU 3 duced). Higgins, Lanza, Laney and Rice [81] I ;1 W'! suggested 10 mgs. per cu.m, for the high quartz 3 rock of the Joplin, Missouri, zinc and lead dis trict. In both of these examples the standards suggested are both practicable and attainable. Russell et al [145] in their granite study in OnJ Barre, Vermont, suggested 9 to 20 million parti n: cles per cubic foot by the impinger sampling icnn trHri ai aQI INDUSTRIAL MEDICINE MS technic and light field counting. Here the dust contained about 35 per cent quartz. In sand stone working, where there is a high percentage of silicates, Badham, in Australia [5] advocated 200 particles per cubic centimeter by Owens' jet dust counter, but hinted that 100 would be better. In Great Britain, perhaps wisely, no figures for permissible dustiness in connection with silicosis have been suggested. In their cement dust study Thompson and his associates [164] investigated one of the most harmless inorganic dusts of modern industry. The effects upon the chests of workers with abundant dust exposure were in no way com parable to the chests of the granite workers de- ^ picted by Russell. Nonetheless, Thompson ad- vocated 10 to 20 million particles per cubic foot as compared with 9 to 20 million for granite. In the case of asbestos dust no figures have as yet been suggested but on the basis of abun dant experience McConnel 1 [ 1 16] of the M etro- _ politan L ife Insurance prefers to see the dust count below 5 million and welcomes still 144 INDUSTRIAL MEDICINE i which the engineer welcomes as an objective of cleanliness for which to strive. Some of these I figures are founded upon reliable data and some are frankly estimates, Legge and Duckering [104], [46] suggested I 0.5 mg. per cu.m. for lead dust which Russell and his colleagues [146] lowered to 0.15 mg. for litharge indicating that this figure might be scaled up or down with changes in the solubility S of the lead compound in serum. T he South African authorities, for their high quartz rock in the Witwatersrand gold mines, have gradually arrived at a figure of about 1 mg. U 'fi per cu.m. and silicosis, under their conditions, _J'i has not been eliminated (although greatly re a ; LU 3 duced). Higgins, Lanza, Laney and Rice [81] I ;1 W'! suggested 10 mgs. per cu.m, for the high quartz 3 rock of the Joplin, Missouri, zinc and lead dis trict. In both of these examples the standards suggested are both practicable and attainable. n: Russell et al [145] in their granite study in OnJ Barre, Vermont, suggested 9 to 20 million parti cles per cubic foot by the impinger sampling icnn traiHri aQI INDUSTRIAL MEDICINE MS technic and light field counting. Here the dust contained about 35 per cent quartz. In sand stone working, where there is a high percentage of silicates, Badham, in Australia [5] advocated 200 particles per cubic centimeter by Owens' jet dust counter, but hinted that 100 would be better. In Great Britain, perhaps wisely, no figures for permissible dustiness in connection with silicosis have been suggested. In their cement dust study Thompson and his associates [164] investigated one of the most harmless inorganic dusts of modern industry. The effects upon the chests of workers with abundant dust exposure were in no way com parable to the chests of the granite workers de- ^ picted by Russell. Nonetheless, Thompson ad- vocated 10 to 20 million particles per cubic foot as compared with 9 to 20 million for granite. In the case of asbestos dust no figures have as yet been suggested but on the basis of abun dant experience McConnel 1 [ 1 16] of the M etro- _ politan L ife Insurance prefers to see the dust count below 5 million and welcomes still 146 INDUSTRIAL MEDICINE lower figures. Merewether [120] gives figures on asbestos dust concentrations but no indica tion of permissible dustiness. In studying metal fume fever caused by breathing freshly formed zinc oxide (Fig. to), Drinker, Thomson, and Finn [43] found that concentrations of 14 mgs. of zinc per cu.m. for 8 hour exposures or 43 mgs. for short exposure could be tolerated without causing the "shakes11 to the average worker. Drinker believed that figures could easily be obtained for other metal lic fumes but the required experiments have never been done. Prodan [138] found that cad mium oxide fume, which is close to zinc oxide metallurgically, was far too toxic to permit breathing measurable amounts. T o insure the avoidance of trouble from chromic acid mist Bloomfield and Blum [15] suggest that continuous daily exposures be kept below 1 mg. per cubic meter and show in their report that this figure is readily attainable by proper transverse ventilation. Cummings [32] sees no need to require the manufacturer of materials with well established INDUSTRIAL MEDICINE 147 harmless effects to maintain air as dean as that demanded in granite cutting. However, there is no longer any excuse for excessive dustiness in any process-- it merely represents slovenly practice. A few years ago it was not uncommon to see workmen employed in an atmosphere so thick with dust that a 50 watt lamp was obscured at a distance of to feet. In a recent lawsuit a witness testified that he had to sweep up every hour because if he waited longer it was necessary to use a shovel 1 Industrial physicians and en gineers have seen these conditions but they can not defend them. T he only justifiable condusion to be drawn from such apparent inconsistencies is that gen erally we lack data for defining rigidly permis sible dustiness. The application of medical and engineering knowledge and common sense to dust control is highly commendable but the point has not been reached where a manufacturer can be told with certainty that his plant w ill have no silicosis, no asbestosis, or no lead poisoning if he keeps dustiness down to some definite figure. H e can be told only that the maintenance of certain 146 INDUSTRIAL MEDICINE lower figures. Merewether [120] gives figures on asbestos dust concentrations but no indica tion of permissible dustiness. In studying metal fume fever caused by breathing freshly formed zinc oxide (Fig. to), Drinker, Thomson, and Finn [43] found that concentrations of 14 mgs. of zinc per cu.m. for 8 hour exposures or 43 mgs. for short exposure could be tolerated without causing the "shakes11 to the average worker. Drinker believed that figures could easily be obtained for other metal lic fumes but the required experiments have never been done. Prodan [138] found that cad mium oxide fume, which is close to zinc oxide metallurgically, was far too toxic to permit breathing measurable amounts. T o insure the avoidance of trouble from chromic acid mist Bloomfield and Blum [15] suggest that continuous daily exposures be kept below 1 mg. per cubic meter and show in their report that this figure is readily attainable by proper transverse ventilation. Cummings [32] sees no need to require the manufacturer of materials with well established INDUSTRIAL MEDICINE 147 harmless effects to maintain air as dean as that demanded in granite cutting. However, there is no longer any excuse for excessive dustiness in any process-- it merely represents slovenly practice. A few years ago it was not uncommon to see workmen employed in an atmosphere so thick with dust that a 50 watt lamp was obscured at a distance of to feet. In a recent lawsuit a witness testified that he had to sweep up every hour because if he waited longer it was necessary to use a shovel 1 Industrial physicians and en gineers have seen these conditions but they can not defend them. T he only justifiable condusion to be drawn from such apparent inconsistencies is that gen erally we lack data for defining rigidly permis sible dustiness. The application of medical and engineering knowledge and common sense to dust control is highly commendable but the point has not been reached where a manufacturer can be told with certainty that his plant w ill have no silicosis, no asbestosis, or no lead poisoning if he keeps dustiness down to some definite figure. H e can be told only that the maintenance of certain