Perfluoroalkyl and polyfluoroalkyl substances (PFASs) comprise a class of over 4,000
human-made chemicals that are commonly used in consumer products and industrial
applications due to their water- and lipid-repellent characteristics. PFASs have been used for
decades in a wide array of products, including food packaging materials, nonstick cookware,
fire-fighting foams, waxes, furniture, stain-repellant fabrics, carpets and pesticides.
In the early 2000s, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS),
considered “long-chain” PFASs because of their eight carbon structure, were voluntarily phased
out by US manufactures due to environmental and human health concerns, leading to a decline
in their use. The continued use of substitute PFASs, however, and the highly persistent nature
and mobility of these compounds has resulted in ongoing environmental PFAS contamination
and human exposure throughout California. These compounds may be airborne, settle into dust
or soil, or be present in drinking water. Consequently, human exposure may occur through
inhalation, ingestion of contaminated drinking water, or non-dietary ingestion when present in
residential environments, the latter of which is typically seen among young children due to hand to-mouth behaviors. As in the general US population, there is widespread PFAS exposure in
California. We identified over a dozen studies reporting detectable levels of PFASs in serum
from California residents, including several large studies conducted by Biomonitoring California,
a collaborative program between the California Department of Public Health (CDPH), California
Environmental Protection Agency’s (Cal/EPA’s) Office of Environmental Health Hazard
Assessment (OEHHA) and Department of Toxic Substances Control.
Following a review of the available scientific literature, we found that there is ample
evidence to demonstrate that exposure to PFASs can lead to adverse health effects in humans.
In this White Paper, we summarized the epidemiological evidence for the health outcomes
identified by the US EPA, C8 Science Panel, ASTDR, and recent systematic reviews of the
literature. The International Agency for Research on Cancer (IARC) and the United States (US)
Environmental Protection Agency (EPA) have classified certain PFASs as possibly carcinogenic
to humans, and OEHHA has listed PFOS and PFOA as a Proposition 65 developmental
Despite the wide variety of chemicals that are classified as PFASs, only PFOA and PFOS
have been studied extensively for their toxicity and fate and transport in the environment. While
there has been extensive monitoring of drinking water for PFASs in California, the relative lack
of data on PFAS levels in air, soil, and dust makes linking PFAS sources to levels in
environmental media and human exposure pathways challenging.
Several California agencies have recently taken steps to better understand and prevent
PFAS exposures from environmental media, including new monitoring and notification water
standards set by the California Water Resources Control Board. The California Air Resources
Board (CARB) and other agencies that are concerned about emissions of these chemicals have
been hampered in their response due to the lack of a standardized methodology for measuring
PFASs in outdoor air.