Per- and poly-fluoroalkyl substances (PFAS) are a group of man-made chemicals that resist heat, oil, stains, grease and water and have been widely used since the 1950s in household and industrial products. While there are many types of PFAS, the most common are those referred to as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Since 1970, firefighting foams containing PFOS and PFOA were widely used in Australia and in other countries because they were highly effective in fighting liquid fuel fires. However, PFAS chemicals do not break down readily in the environment, can travel long distances through soil and water and can get into groundwater. PFAS levels build up in animals and humans and remain for many years in the human body.

In Australia, decisions were made about 10 years ago to phase out the most concerning PFAS chemicals, including the firefighting foams, to reduce human exposure. Recently, a number of communities close to where these fire-fighting foams were used in the past have been advised to lessen further exposure by not drinking contaminated water sources and eating foods with high levels of PFAS.

It is not practically possible to prevent all PFAS exposure due to the large number of sources from which people may still get very low exposures. Internationally, everyone generally has low levels of PFAS chemicals in their blood. In other countries, people in highly exposed communities (for example, people who live near manufacturing plants where PFAS is made or used), typically have PFAS concentrations up to 10 times higher than those in the general population. In Australia, fire fighters may have concentrations up to 10 times higher. Workers in overseas PFAS manufacturing plants have been found to have PFAS concentrations up to 1,000 times higher than the general population. There are no PFAS manufacturing plants in Australia.

In Australia, available evidence indicates that the amount of the chemical PFOS in the blood is generally higher than PFOA in the general population. It is important to note that many overseas studies relating to workers in manufacturing plants have focussed more on PFOA.