a combustible gas consisting chiefly of methane, formed especially in coal mines, and dangerously explosive when mixed with certain proportions of atmospheric air.
the explosive mixture itself.
a mixture of hydrocarbons, chiefly methane, formed in coal mines. It forms explosive mixtures with air
Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
It was strongly and widely believed that when a mine explosion occurred, a flammable atmosphere of firedamp must be present.
Shortly after the day shift began work a violent explosion of firedamp took place.