Final Report: Mining Environmental Target Investigation Of Kaolin Clay Mining And Milling.
A preliminary investigation was conducted by NIOSH of the kaolin mining industry. The investigation was limited to literature reviews, data gathering efforts, and industrial hygiene field surveys. In 1980, approximately 8 million tons of kaolin were produced in the United States by 119 mines. Nearly all of these mines were associated with some type of milling operation. The industry employed approximately 4,500 workers; about 900 of these were involved in the actual mining process. The majority of the employees were associated with the milling operation. Environmental data collected at 16 kaolin operations showed respirable silica (14808607) dust concentrations ranging from 0.44 to 1.30 milligrams per cubic meter (mg/m3). Total nuisance particulates ranged from 11.82mg/m3. Approximately 25 percent of the total nuisance dust samples collected were above the NIOSH standard. Published animal and in-vitro investigations indicated that kaolin dust had the ability to elicit pulmonary responses pathologically characterized as reticulum formation and disease of the connective tissue. Macrophage activity was also observed. Epidemiological reports stated that kaolin workers had a 1 to 10 percent incidence rate for pulmonary fibrosis. The author concludes that existing evidence neither proves nor disproves that kaolin poses a fibrogenic hazard to lungs. Continued laboratory, engineering, and environmental investigations are suggested.
NIOSH-Author; Mining-industry; Airborne-dusts; Aerosol-particles; Risk-factors; Biological-effects; Industrial-medicine; Occupational-respiratory-disease;
NTIS Accession No.
Mining Surveillance Team, Environmental Investigation Branch, NIOSH, NTIS PB83-207-720, 29 pages, 39 references