Copper 1 : A reddish-brown, malleable, ductile, metallic element (Cu) that is an excellent conductor of heat and electricity and is toxic and flammable in its very finely divided form
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}