| Abstract |
Worker exposures to respirable mineral fibers, total airborne dust, free silica (7631869), trace metals, carbon-monoxide (630080) and noise were surveyed at Johns-Manfille (SIC-3296) in Alexandria, Virginia from April 11 to 15, 1975. The factory employed about 388 workers. Acoustical ceiling boards and tiles were produced on a four shift, 7 day week basis. First aid was administered by supervisors. Pre-employment examinations included chest X-rays, urinalysis and blood tests. There were also voluntary biannual examinations. A local physician was retained as a medical consultant. Industrial hygiene and safety programs were implemented. Personal protective equipment was used. Personal, general air and bulk samples were collected and analyzed. In the main panel line and the tile areas, the highest fiber concentrations were 1.9 and 2.04 fibers per cubic centimeters (fibers/cc), respectively. The highest time weighted average (TWA) fiber concentrations in the panel area and tile productionarea were 0.88 and 1.95 fibers/cc, respectively; and the mean TWA fiber exposures were 0.55 and 0.66 fibers/cc, respectively. TWA total airborne dust concentrations ranged from 0.85 to 14.72 milligrams per cubic meter (mg/cu m) and from 1.03 to 28.55 mg/cu m in the panel and tile areas, respectively. Twelve of the 46 samples of TWA concentrations exceeded 10 mg/cu m. In the panel and tile areas count, median airborne fiber diameters averaged 2.1 and 2.2 micrometers, respectively, and lengths averaged 15.5 and 17.0 micrometers, respectively. TWA free silica concentrations ranged from 0.60 to 1.02 and 0.09 to 260 mg/cu m in the panel area and in the tile area, respectively. The highest carbon-monoxide concentration was 94 parts per million (ppm). The TWA concentration for the 21 hour sampling period was 35.4ppm. Trace metals were below detectable concentrations, except zinc (7440666) which ranged from 3 to 10 micrograms per cubic meter. Noise levels ranged from 75 decibels (dB) on the A scale to 96dB on the C scale. The author concludes that concentrations of total airborne dust in the panel and tile areas and free silica in the clay and paint mix areas are excessive. He recommends further sampling for carbon-monoxide in the cupola changing areas and medical surveillance of workers exposed to mineral fiber. |
