Firefighting foams fall into two main categories, Class A and Class B. Class A foams are used to fight fires caused by wood, paper, and plants. They generally do not contain PFAS chemicals. Class B foams put out fires caused by flammable liquids like gasoline, oil, and jet fuel. They may contain PFAS chemicals. The Hazardous Materials and Waste Management Division regulates Class B firefighting foam containing PFAS (PFAS AFFF) in accordance with 6 CCR 1007-3, Part 267, Subpart Q
