California EPA Adopts Public Health Goals for PFOA and PFOS

April 09, 2024

The California Environmental Protection Agency (CalEPA) on April 5 set new public health goals for two per- and polyfluoroalkyl substances (PFAS) in drinking water, signaling the possibility of strict regulation by the state.

CalEPA’s Office of Environmental Health Hazard Assessment (OEHHA) adopted public health goals (PHGs) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in drinking water of 0.007 parts per trillion (ppt) and 1 ppt, respectively.

Although they are nonenforceable advisory levels, PHGs reflect regulators’ current analyses of potential health risks and signal where enforceable standards may ultimately be set. OEHHA’s PHGs for PFOS and PFOA, which are set at a level of risk of one additional cancer case per one million persons exposed over a lifetime, are significantly lower than the 4 ppt level that can reliably be detected with present-day technology.[1] The PHGs for noncancer risks—3 ppt for PFOA and 2 ppt for PFOS—are also lower than current detection limits.

Regulatory Trends

PFOA and PFOS, the two most-studied PFAS, have been used for decades in a variety of industrial, commercial, and consumer products because, among other things, they can be exceptionally resistant to heat and moisture. The resilience that makes these chemicals useful, however, also causes them to persist in the environment without breaking down easily.

That durability, combined with their ubiquity, has raised concerns at the state and federal levels about potential links between PFOA and PFOS and various health risks, and has spurred significant regulatory action over the past several years to further study, remediate, and ultimately restrict PFAS usage. California’s adoption of extremely low PHGs for PFOS and PFOA is part of a continuing trend toward vigilance as the science around health effects associated with PFAS exposure continues to develop.

In setting these PHGs below current detection limits, California is following in the footsteps of the US Environmental Protection Agency (EPA), which issued similarly low nonbinding health advisories for PFOA, PFOS, and certain other PFAS chemicals in 2022. Those health advisories were later followed by proposed maximum contaminant levels (MCLs) for six PFAS chemicals under the Safe Drinking Water Act, including PFOA and PFOS at the present detection limit of 4 ppt. With the White House Office of Management and Budget having completed its review of the proposed MCLs at the end of March 2024, EPA is expected to finalize the proposed MCLs any day.

If California follows EPA’s path toward final, enforceable drinking water standards, it is likely the state—acting through the State Water Resources Control Board—would similarly set MCLs that reflect current technological capabilities, notwithstanding that its health advisory levels may be considerably lower. Notably, the state cannot set MCLs that are less protective of human health than federal levels; and if the EPA’s final drinking water rule is consistent with its proposed MCLs, the federal limit would already be as low as current technology allows.

Looking Ahead

California’s movement toward strict MCLs for PFOA and PFOS may serve as a backstop for the state to enforce its own drinking water standards in the event federal MCLs are loosened, whether as a consequence of the 2024 presidential election or for any other reason. Setting its own MCLs will also allow the state to be nimbler in revising those numbers if and when technological progress enables reliable detection of PFAS chemicals at lower levels. Whatever the motivation, California’s adoption of ultra-low PHGs is a clear signal that PFAS will remain in the state’s crosshairs for the foreseeable future.


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[1] EPA recognized 4 ppt as the current reliable detection limit for both PFOA and PFOS in its pending National Primary Drinking Water Standard for PFOA and PFOS under the Safe Drinking Water Act. See 88 Fed. Reg. 18666 (March 29, 2023).