Monitoring of workers exposure to low levels of airborne monomers in a polystyrene production plant.

Exposure of workers to sub-ppm levels of airborne monomers, namely ethyl acrylate, methyl methacrylate, n-butyl acrylate, styrene, alpha-methylstyrene, and 2-ethylhexyl acrylate, in a polystyrene production plant was measured in the same sample on a single gas chromatographic column. The best separation and sensitivity were obtained with a 3 m X 3.175 mm stainless steel column packed with 10% FFAP on Chromosorb and a temperature programmed from 70 degrees C to 110 degrees C. A total of 106 air samples were collected on 150 mg charcoal tubes from the breathing zone of workers, from areas near reactors, and from places where monomers were unloaded from trucks and tank cars. Samples were analyzed in a manner similar to the method recommended by NIOSH. The mean TWA concentrations in a worker's breathing zone were 89, 66, 49, 120, 41 and 1 ppb for ethyl acrylate, methyl methacrylate, n-butyl acrylate, styrene, alpha-methylstyrene, and 2-ethylhexyl acrylate, respectively. The highest TWA breathing zone concentration was 14.8 ppm for styrene, which occurred during unloading and sampling of the monomer for a quality check. The mean TWA concentration of monomers in the air of the workplace were 1.1 ppm, 169, 36, 54, 10, and 30 ppb for the same 6 compounds mentioned above. The highest area TWA concentration was 57 ppm for ethyl acrylate, which occurred outdoors at the truck and tank car unloading site. It was concluded that use of two separate local exhaust ventilating systems in this polymerization process were effective in maintaining negative pressure within the reactors under all circumstances of use. These engineering controls and care in handling monomers have resulted in a relatively safe working environment.