EPA’s health advisories are based on the best available peer-reviewed studies of the effects of PFOA and PFOS on laboratory animals (rats and mice) and were also informed by epidemiological studies of human populations that have been exposed to perfluoroalkyl substances (PFASs). These studies indicate that exposure to PFOA and PFOS over certain levels may result in adverse health effects, including developmental effects to fetuses during pregnancy or to breastfed infants (., low birth weight, accelerated puberty, skeletal variations), cancer (., testicular, kidney), liver effects (., tissue damage), immune effects (., antibody production and immunity), thyroid effects and other effects (., cholesterol changes).
Perfluoroaromatic compounds can be manufactured via the Fowler process, like fluoroalkanes, but the conditions must be adjusted to prevent full fluorination. They can also be made heating the corresponding perchloroaromatic compound with potassium fluorine at high temperature (typically 500 °C), during which the chlorine atoms are replaced by fluorine atoms. A third route is defluorination of the fluoroalkane; for example, octafluorotoluene can be made from perfluoromethylcyclohexane by heating to 500 °C with a nickel or iron catalyst. 
Other minerals such as topaz contain fluorine. Fluorides, unlike other halides, are insoluble and do not occur in commercially favorable concentrations in saline waters.  Trace quantities of organofluorines of uncertain origin have been detected in volcanic eruptions and geothermal springs.  The existence of gaseous fluorine in crystals, suggested by the smell of crushed antozonite , is contentious;   a 2012 study reported the presence of % F
2 by weight in antozonite, attributing these inclusions to radiation from the presence of tiny amounts of uranium .