What is the primary ingredient used in Class B extinguishers?

The primary ingredient used in Class B extinguishers is sodium bicarbonate. Class B fire extinguishers are specifically designed to combat fires fueled by flammable liquids such as gasoline, oil, and paint. Sodium bicarbonate acts effectively in smothering the flames by releasing carbon dioxide when heated, which displaces oxygen and helps to prevent re-ignition.

This makes sodium bicarbonate a versatile choice for extinguishing Class B fires, where controlling and putting out flames quickly is crucial to prevent further spread. Other agents used in Class B extinguishers include foam and dry chemical agents, but in the context of this question, sodium bicarbonate is highlighted as the primary active component due to its effectiveness in tackling flammable liquids.