Fire extinguisher had been developed by DuPont and the US Army in 1954. Both 1211 and 1301 work by inhibiting the chain reaction of the fire, and in the case of Halon 1211, cooling class A fuels as well. Halon is still in use today but is falling out of favor for many uses due to its environmental impact. Europe and Australia have severely restricted its use, since the Montreal Protocol of 1987. Less severe restrictions have been implemented in the United States, the Middle East, and Asia. Internationally there are several accepted classification methods for hand-held fire extinguisher. Each classification is
Fire extinguisher reaching it. Unlike powder, foam can be used to progressively extinguish fires without flashback. Cools burning material. Very effective against fires in furniture, fabrics, etc. (including deep-seated fires), but can be safely used only in the absence of electricity. Wet chemical (potassium acetate, potassium carbonate, or potassium citrate) extinguishes the fire by forming an air-excluding soapy foam blanket over the burning oil through the chemical process of saponification (an alkali reacting with a fat to form a soap) and by the water content cooling the oil below its ignition temperature. Generally, class A and K (F in Europe) only, although