Toxicity of smoke during chair smoldering tests and small scale tests using the same materials

Toxicological evaluation of smoke produced during smoldering chair tests was undertaken by exposing mice to smoke emitted prior to, as well as following, flaming ignition of the chairs. By exposing several groups of mice, using undiluted smoke from the room containing the chairs, as well as various dilutions of the smoke, different levels of acute lethality were obtained. From these experiments, chairs constructed with polyurethane foam were found to create higher toxic atmospheres than chairs constructed with polyester or cotton fiber cushions. The same materials (polyurethane foam, polyester and cotton fibers) were also thermally decomposed in a small scale system and mice were exposed to the smoke to evaluate acute toxicity. Again polyurethane foam was found to produce smoke more toxic than smoke produced by polyester and cotton fibers. Sensory irritation monitored in mice during the smoldering tests indicated that an intense level of irritation was present long before large amounts of smoke were generated and long before flaming ignition occurred. The phenomenon of eye, nose and throat irritation would therefore be the first effect impeding escape attempts of individuals in a fire situation. Sensory irritation was followed by asphyxiation as evolution of carbon monoxide or hydrogen cyanide, or both, occurred. The same pattern of responses was observed with smoke generated with the small scale decomposition system.