Synthetic foams are based on synthetic surfactants. They provide better flow and spreading over the surface of hydrocarbon-based liquids, for faster knockdown of flames. They have limited post-fire security and are toxic groundwater contaminants.
* Aqueous film forming foams (AFFF) are water-based and frequently contain hydrocarbon-based surfactants such as sodium alkyl sulfate, and fluorosurfactants, such as fluorotelomers, perfluorooctanoic acid (PFOA), or perfluorooctanesulfonic acid (PFOS). 
* Alcohol-resistant aqueous film-forming foams (AR-AFFF) are foams resistant to the action of alcohols and can form a protective film.
*Fluorine-free foams (FFF, also called F3) are mostly based on hydrocarbon surfactants and are free of any fluorosurfactant.