Extinguishing Agent 3 : A substance that puts out a fire by cooling the burning material, blocking the supply of oxygen, or chemically inhibiting combustion
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}