A gas that, in the pure state or as commercially produced, will vigorously polymerize, decompose or condense, become self-reactive, or other wise undergo a violent chemical change under conditions of shock, pressure, or temperature. NFPA 55, 2005 ed
National Fire Protection Association, Illustrated Dictionary of Fire Service Terms, Jones & Bartlett Publishers, MA. USA 2006. https://books.google.com.kw/books?id=W0WIRa3Gl4QC& printsec=frontcover&source=gbs_ge_summary_r&cad=0# v=onepage&q&f=false, (Fr Srvc - Amer) {141}