Butadiene 2 : A colorless gas (C4H6) with a flash point of -105?F, an ignition temperature of 788?F, and explosive range of 2 to 12 percent, which is moderately toxic and used in the synthesis of rubber
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}