Abstract
Although toluene diisocyanate (TDI) has been widely used for about 50 years, industrial hygiene characterizations of other chemical exposures used in conjunction with TDI have generally received much less attention. As part of a retrospective, cohort mortality study, industrial hygiene evaluations were performed in three facilities manufacturing flexible (TDI-based) foam. This report is concerned only with nonisocyanate exposures in that industry.
In each facility, the concentrations of several air contaminants, other than TDI, were assessed, including aliphatic amines, nitrosamines, nitrogen dioxide, thermal degradation products, organic solvents, polyurethane dust, and flame retardants. Air samples were also collected for subsequent assay of mutagenic activity using Salmonella bacterial tester strains TA98 and TA100.
Workers were found to have respiratory and probably dermal exposure to methylene chloride in each facility. Traces of nitrogen dioxide and some aliphatic amines were evident. However, N-nitrosamines were not found. Exposure to thermal degradation products, polyurethane dust, and to flame retardants does not appear to be a problem under reasonable hygienic conditions. However, evidence for the existence of acrolein and acrylonitrile was found in one facility due to the thermal degradation of finished foam. Mutagenic activity, appearing only in the particulate fraction, appeared highest when the total isocyanate group air concentrations (TRIG) were also high. In one facility, the mutagenic activity was up to 75 times higher than the mutagenic activity of the outside air. The methods used to characterize each of the exposures are provided and the results are discussed.