Polyurethane 3 : A plastic, often used as insulation, that comes in both rigid and elastic foam forms; it is combustible and its combustion products are toxic
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}