Document GEqjOgvkGJMRx0gzw9Q1kRyY

PLAINTIFF'S EXHIBIT <l69999GiS OWl P TOXIC HAZARDS* Asbestos-! Mbi'Hos is a harmful dusr. containing chit'flv Indrntcd magnesium silicate, and occurs as a white, fibrous ore It is used in a variety of products: it may be spun into yarn: the longer fibers are used in the manufacture of cloth, braid, rope and theater curtains: and the shorter fibers are used in the manufacture of insulating boards, felt, paper and cardboard, and in the manufacture of brake linings. Workers engaged in the extraction and manu facture of asbestos, especially spinning and weaving opera tions, are exposed to the dust. When inhaled, asbestos causes asbestosis. in which the lung tissue be< omes fibrosed. Exposures of four to seven years are necessary for the production of serious asbestosis The signs and symptoms are those of pulmonary fibrosis, consisting of cough, shortness of breath, weight loss and easv fatigability. In the later stages there may be clubbing of the fingers, increase in the diastolic blood pressure and rales. X-ray study reveals a granular ground-glass t>pe of change, particularly in the lower-lung fields, and the pleura mav be thickened. In silicosis, [he entire lung field is equally involved, whereas in asbestosis most of the fibrosis is in the lower third or half of rhe long. Vsbestos dust should not be allowed to contaminate the worker's atmosphere. It should be controlled at the point ot origin by use of local exhaust systems or wet methods. Approved dust-tvpe respirators may be used for brief periods. W hen asbestos is used, the atmosphere should be periodically i hecked for the number of particles in the air. The maximum allowable concentration is 5.000,000 par ticles per cubic foot of air. Only the fibers that are less than 3 microns in diameter 0.03 mm. I are respirable. Persons with previous pulmonary or cardiac disease should not be employed where exposure to asbestos dust is a problem. % X-ray study of the chest and physical examinations annually should be required of all persons employed in dusty asbestos operations. George E. Morris. M.D. Bibliography Asbestos ; Department of Labor and Industries, Bulletin. 492., Prepared b\ the Commonwealth of Massachusetts, Division ol Occupational Hygiene, Boston, Massachusetts. February, 1959. Occupation and Health. 2 voi. iDepartment of International Labour Office.! Prepared bv the World Health Organization, Geneva. Switzerland, 1930. *This is one of a senes of articles published co-operatively by the Committee on Industrial Health and the Panel on Child Health of the Committee on Public Health ol the Massachusetts Medical Society. The panel provides liaison with the Massachusetts Chapter ol the Ameri can Academy of Pediatrics, whose Boston and Worcester Poison Informa tion Centers are activities of the Committee on Accident Prevention. + From the Committee on Industrial Health, George F. Wilkins. M.D.. chairman: Karl T. Benedict. M D.; Harriet L. Hardy, MD.. George B. Morris, M.D.. Robert C. Thompson, M.D.; Robert L Quimbv, IC.lL, and H enrv F Howe. M D \ -*#