HHE Report No. HETA-78-034-930, Homestake Mining Company, Lead, South Dakota.
Environmental and personal air samples were analyzed for lead (7439921), mercury (7439976), silica (7631869), total and respirable dust, asbestos (1332214), hydrogen-chloride (7647010), manganese (7439965), iron-oxide (1309371), chromium (7440473), total welding fumes, toluene (108883), and xylene (1330207), and medical surveys were conducted at the Homestake Mining Company (SIC-3330) in Lead, South Dakota on February 28, and May 15, 1978. A representative of the United Steelworkers of America, Local 7084, requested the evaluation on behalf of workers in the milling operation, refinery operation, and the assay office. All personal air samples for lead in the refinery and furnace area of the assay office contained concentrations above the OSHA standard of 50 micrograms per cubic meter ranging from 67 to 12,300 micrograms per cubic meter. Two of three air mercury samples in the refinery and the mill exceeded the NIOSH recommended standard of 0.050 milligrams per cubic meter (mg/CuM), ranging from 0.048 to 0.070mg/CuM. In the assay office, all air samples for respirable silica exceeded the NIOSH recommended standard of 0.05mg/CuM, ranging from 0.15 to 1.33mg/CuM. Three of nine samples for respirable particulate dust exceeded the American Conference of Governmental Industrial Hygienists standard of 5.00mg/CuM, ranging from 0.36 to 22.28mg/CuM. Asbestos air concentrations were less than the NIOSH recommended standard of 0.1 fibers per cubic centimeter. All six air samples for hydrogen- chloride in the refinery were below the OSHA standard of 7.0mg/CuM. Total and respirable particulate dust concentrations in the furnace charging operation exceeded their corresponding standards. The authors conclude that a health hazard from overexposures to lead, mercury, silica, and total respirable particulates existed at this facility. They recommend worker education, medical surveillance, and several control measures.
Hazard Evaluations and Technical Assistance Branch, NIOSH, Cincinnati, Ohio, 27 pages, 22 reference