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FILE NAME: National Safety Council (NSC) DATE: 1942 Jan DOC#: NSC190 DOCUMENT DESCRIPTION: NSC - National Safety News - The Working Environment The Working Environment By MYRON A. SNELL Suin'rrisiiiQ Iinyineer, H ar tford Accident <tnd Indemnity Co,, Hartford, Conn. ASAFE and healthful place for work should be the aim of . e v e r y industrial establish ment. Such an environment can be gases or vapors. Solid dispersoids may be divided into dusts, fumes and smokes. Liquid dispersoids may be grouped into mists and fogs. free silica and asbestos may cause silicosis and asbestosis if inhaled in sizes below ten microns in sufficient concentrations over a long enough achieved only through a study of period of time. every condition of industrial life, fol lowed by an adjustment of these con ditions to the health requirements of the worker. Those factors which have a bearing on morale and efficiency, as well as on health, should also be con sidered. Dusts Industrial dusts are mechanically generated by many processes. Typ ical examples are drilling, blasting, and crushing in mining and quarry ing; polishing, buffing and grinding in metal finishing, and stone-cutting, Other dusts, with the exception of metallic dusts, do not result in dis eases, but many of them do produce certain changes in the lungs which evidently are not of great importance. Nevertheless, workers should not be allowed to inhale high concentrations Employees should not be exposed to polishing and abrasive blasting in the of any kind of dust. the inhalation of atmospheric contam granite and monument industry. In Permissible limits for these dusts I inants in sufficient concentrations to these examples the dust is of the inor have been established by various or endanger health, nor even to cause ganic or mineral variety. Animal and ganizations, but as yet there has been any marked discomfort. Employees vegetable dusts, known as organic no complete agreement for dust con who are satisfied with the working en dusts, are generated by such opera centrations in workroom atmospheres. vironment are happier and more effi tions as cotton processing, wood-work The American Standard Safety Code cient, as well as healthier. Many in ing. and polishing skins. for the Protection of Heads, Eyes and dividuals imagine all sorts of ill From the health standpoint, indus Respiratory Organs recommends "that effects from even trivial industrial ex trial dusts above ten microns in size no worker be continuously subjected posures. They may even worry them are of ho importance because they are without a protector to any atmos selves into actual illness which was too large to be inhaled into the lungs. phere containing any form of mineral caused by mental attitude rather than Dusts below ten microns in size are dust in quantity exceeding 50,000,000 environment. not visible to the naked eye but can particles per cubic foot of a size less Atmospheric contaminants in in be seen with a microscope down to than five microns." dustrial plants may consist of solid about two-tenths of a micron. Dusts The National Silicosis Conference dispersoids, liquid dispersoids. or containing sufficient percentages of in 1937 suggested that the maximum 72 N ational S a fe ty News, J a n u a ry , 7942 I".-- - V ; permissible concentration should be lead, 0.15; mercury, 0.1; zinc, 15.0. V found by multiplying the percentage of free silica by the total dust count. If the result is over live million, the concentration may be considered loo AIDS TO A HEALTHFUL INDUSTRIAL ENVIRONMENT 1. N ecessary changes in o p e ra tio n s or processes, m aterials, techniques, or equipm ent. Very little work has been done on concentrations of smoke which can be tolerated without impairing efficiency or causing marked discomfort, and no ' l . high. 2. Enclosing or isolating h a ia rd o u s ex limits have yet been established. % California, Connecticut and some posures. I other states allow no more than five 3. G ood housekeeping and exhaust ventilation. Mists and Fogs ? million particles of dust running high 4. P ersonal p ro te c tiv e equipm ent. Mists are formed by the mechanical %' in free silica. New York State, in the 5. S an itatio n and re la te d facilities. disintegration of a liquid by such proc Industrial Code adopted September 1, 6. C ontrol of te m p e ra tu re and hu esses as spray coating of paints or K 1941, for the control of silica dust |[; in the stone cutting and stone finish- midity. 7. S atisfacto ry illumination. vitreous enamels. They usually range ifr: ing industry, allows five million par- 8. Noise co n tro l. in size from 50 to 100 microns. | tides if the dust contains more than 9. A d eq u ate m edical c a re . Fogs are formed by the condensa 70 per cent free silica, 10 million par- 10. Good w ages and sa tisfa c to ry work tion of vapors. They vary in size from M tides if it contains from 10 to 70 per ing hours. 11. An efficient personnel d e p a rtm e n t. 5 to 50 microns. Wherever hot alka line cleaning or pickling vats are oper q cent, and 100 million particles if it *,, contains less than 10 per cent free 12. Employee training. ated in a rather cool workroom, the silica. California has established a water vapor is apt to condense in the -,j~- permissible limit of five million par- form of a fog in the same manner that i tides per cubic foot of air for asbes- As yet, no definite standards have ordinary fog is formed outdoors. tos dust. been established for most of the toxic A mist which may be inhaled in *' Metallic dusts may also be gener metals. The American Standards As spray coating operations may be ated mechanically in such operations sociation's Sectional Committee on rather complex in nature. In the case as weighing and mixing red lead and Allowable Concentrations of Toxic of spraying paints, it usually consists ^ litharge in the manufacture of paints Dusts and Cases is developing stand of a mixture of organic solvents of and storage batteries. Permissible ards for cadmium, chromium, lead varying toxicity together with solid limits for such toxic dusts are the and mercury. They also propose to matter in solution or in suspension. same as for the fumes of these metals. develop standards for antimony, ar These fine droplets in the form of mist senic, manganese and zinc. All of may hold in suspension lead oxide as Fumes and Smokes these standards will undoubtedly be a pigment or other particles of a toxic- available in the near future. nature. Inhalation of the freshly formed In the spray coating of vitreous en fume of any metal in sufficient con The Journal oj Industrial Hygiene amels a water vehicle is used but the centration may cause the condition and Toxicology (June, 1940) pub particulate matter in suspension may known as "metal fume fever," also lished a Code for Safe Concentrations contain toxic metals in the form of known as zinc chills or shakes. Al of Certain Common Toxic Substances oxide, such as cadmium, lead and though this condition causes a great Used in Industry. This code con manganese. In addition, they some deal of discomfort and may be alarm tained a list of suggested permissible times contain finely divided particles ing to those who are not familiar with limits to be used as a guide until the of free silica in the form of quartz or - it, it is actually not a disease and has ASA had completed its standards. flint. A . no permanent effect on the individual. Maximum allowable concentrations The maximum allowable concen Inhalation of dust or fumes of the for certain of the toxic metals, ex tration in inspired air containing mist If-' toxic metals in sufficient quantities pressed in milligrams per cubic meter is the same as that for vapors, fumes :'p, can also cause systemic poisoning. were: Cadmium, 0.1; chromium, 0.1; (Continued on page 66)