Quantitation of employee exposure to emission products generated by commercial-scale processing of polyethylene

Although considerable research has been performed on the thermal degradation products of polyethylene, no data that can be compared to occupational exposure limits have been reported on the exposure of workers in commercial polyethylene extrusion operations. In this study, the actual airborne concentrations of previously identified analytes were measured during the commercial-scale processing of polyethylene resins. Nine polyethylene resins, spanning LDPE, LLDPE, and HDPE product slates were processed under commercial-scale conditions appropriate to their application: blown film, extrusion coating, blow molding, pipe extrusion, and rotational molding. Air samples were taken from operator breathing zones and of representative workplace air and contained air (inside film bubbles and molded parts) using recognized occupational health and safety protocols. The compounds selected for monitoring consisted of aldehydes (formaldehyde, acetaldehyde, acrolein, butyraldehyde, crotonaldehyde, and benzaldehyde), aromatics (benzene, toluene, xylenes, and styrene), formic and acetic acids, furan and tetrahydrofuran, and acetone. Airborne particulates also were measured. Of the 450 concentration measured from workplace air and operator breathing zones, 440 were below detection limits. Nine of the remaining ten concentrations were < 10% of the established exposure limits, while one particulate measurement was < 50% of the established exposure limit. As well, 180 contained-air samples were taken. Off-gases trapped inside film bubbles and molded parts accumulated to concentrations above those measured in the ambient air. It was concluded that polyethylene extrusion presents minimal inhalation hazards in a moderately ventilated environment.