A 27-page review of short term toxic gas emissions from polyurethane foams in fires is published in Fire Science Reviews. World use of polyurethanes (foams, solid) is estimated at c. 18 million tonnes (2016), up from 14 Mt (2010), with furniture foam and building insulation the main applications (28%, 25%).
Polyurethanes are a widely varying family of polymers based on the nitrogen – carbon – oxygen urethane (carbamate) group. Like all combustible materials, polyurethanes emit toxic and/or irritant gases which can inhibit escape from a fire in case of incomplete combustion: carbon monoxide (CO), hydrogen cyanide (HCN), nitrogen oxides, isocyanates, hydrogen halides. Real uncontrolled fires, though, are always under-ventilated. The authors review data available, noting that there is a lot of fire test data but that toxic emissions depend strongly on fire conditions (temperature, oxygen availability, and development of these over time) making it very difficult to derive relevant information from bench tests. They also conclude that there is some contradiction in the literature concerning the impact of flame retardants on fire toxicity of polyurethane foams, but that “A large majority of the literature indicates that the addition of fire retardants does not increase toxicity of polyurethane foams.”
“The fire toxicity of polyurethane foams”, A Review, S. McKenna & T. Hull, Fire Science Reviews, 2016 (5:3), open access https://dx.doi.org/10.1186/s40038-016-0012-3