Fluorosurfactants, or fluorinated surfactants, are synthetic organofluorine chemical compounds that have multiple fluorine atoms. They can be polyfluorinated or fluorocarbon-based (perfluorinated). As surfactants, they are more effective at lowering the surface tension of water than comparable hydrocarbon surfactants. They have a fluorinated "tail" and a hydrophilic "head." Some fluorosurfactants, such as PFOS, are detected in humans and wildlife.