A Review of tbe Literature on tbe Gaseous Products and Toxicity Generated from the Pyrolysis and Combustion of Rigid Polyurethane Foams*

The literature on rigid polyurethane foam has been reviewed with an emphasis on the gaseous products generated under various thermal decomposition conditions and the toxicity of those products. This review is limited to publications in English through 1984. Carbon monoxide (CO) and hydrogen cyanide (HCN) were the predominant toxicants found among more than a hundred other gaseous products. The generation of CO and HCN was found to increase with increasing combustion temperatures. Many test methods were used to assess the acute inhalation toxicity of combustion products from various rigid polyurethane foams:. Lethality, incapacitation, physiological and biochemical parameters were employed as biological end points. In general, the combustion products generated from rigid polyurethane foam in the flaming mode appear to be more toxic than those produced in the non-tlaming mode. The LCso vaIuesfor 3O-min exposures ranged from 10to 17mgl-1 in the tlaming mode and weregreaterthen34mgl-1 in the non-flaming mode. With the exception of one case, in which a reactive type phosphorus containing fire retardant was used, the addition of fire retardants to rigid polyurethane foams does not appear to generate unusual toxic combustion products.