What chemical is in a fire extinguisher?
Fire extinguisher
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The carbon dioxide (CO2) extinguisher was invented (at least in the US) by the Walter Kidde Company in 1924 in response to Bell Telephone's request for an electrically non-conductive chemical for extinguishing the previously difficult-to-extinguish fires in telephone switchboards. It consisted of a tall metal cylinder containing 7.5 pounds (3.4kg) of CO2 with a wheel valve and a woven brass, cotton covered hose, with a composite funnel-like horn as a nozzle. CO2 is still popular today as it is an ozone-friendly clean agent and is used heavily in film and television production to extinguish burning stuntmen.[9]  Carbon dioxide extinguishes fire mainly by displacing oxygen. It was once thought that it worked by cooling, although this effect on most fires is negligible. This characteristic is well known and has led to the widespread misuse of carbon dioxide extinguishers to rapidly cool beverages, especially beer.