On September 29, 2022, The World Health Organization (WHO) published its draft guidance on perfluorooctanoic acid (“PFOA”) and perfluorooctane sulfonate (“PFOS”) in drinking water, which are the most widely studied of the per- and polyfluoroalkyl substances (PFAS). PFAS are a vast group of man-made chemicals found in many consumer products due to their desirable chemical properties. PFAS, however, resist degradation and, in some cases, have migrated into soil and groundwater, which created concern regarding its environmental and human health impact. As a result, a number of government agencies, including the US Environmental Protection Agency (“EPA”) and a number of state governments, have issued recommendations and/or imposed maximum limits on PFAS in drinking water.

In 2016, the EPA issued Lifetime Health Advisories (“LHA”) for PFOA and PFOS of 70 parts per trillion (“ppt”) in drinking water. Since that time, a number of states have issued more stringent maximum contaminant levels for PFAS, including PFOA and PFOS. For instance, California has set notification levels as low as 5.1 ppt for PFOA and 6.5 ppt for PFOS. In addition, earlier this year EPA issued new LHAs for PFOA and PFOS that reduced the recommended levels to 0.004 ppt for PFOA and 0.02 ppt for PFOs. Those levels are 17,500 times and 3,500 times, respectively, lower than EPA’s prior LHAs, and levels that are essentially zero, as current techniques are unable to detect PFAS at those levels. While EPA asserted that its revised LHAs are based on emerging science, a number of groups have criticized EPA’s actions and called into question the scientific basis for its new LHAs. In fact, the American Chemistry Council (“ACC”) recently filed suit against EPA seeking to challenge the new LHAs for PFAS, noting that “EPA’s revised [LHAs] for PFOA and PFOS reflect a failure of the Agency to follow its accepted practice for ensuring the scientific integrity of its process.” The WHO’s draft guidance lends support to those, including the ACC and National Academy of Sciences, who have criticized EPA’s LHAs. Based on its review of the current scientific and medical studies, the WHO recommends a limit of 100 ppt for PFOA and PFOS in drinking water, a limit that is 25,000 times higher than that which the EPA recommends. In addition, Health Canada recently issued its guidance for PFOA and PFAs in drinking water. It recommends limits of 200 ppt for PFOA and 600 ppt for PFOS, further calling into question EPA’s LHAs.

While the WHO’s guidance is significantly at odds with that of the EPA’s, many are stating that this difference underscores the amount of uncertainty with regard to the impact of PFAS on human health. In issuing its recommendation, the EPA found its recommended limit to be at a “level of drinking water contamination below which adverse health effects are not expected to occur,” while WHO concluded that “uncertainties in identifying the key endpoint applicable to human health following exposure to PFOS and/or PFOA are too significant to derive a Health Based Guidance Value (HBGV) with confidence.” However, WHO determined that “due to the potential adverse health effects reported in both humans and animals following higher level exposure to PFOS and/or PFOA” a guidance value for PFOA and PFOS in drinking water was warranted. It is important to keep in mind that WHO is a global entity that considers in its guidance countries around the world, some of which may not have the technological capabilities to remediate PFAS in drinking. Additionally, WHO’s draft guidance is only a background document, which is open for public comment until November 11, 2022, and can potentially change.

EPA plans to issue binding maximum contaminant levels for PFOA and PFOS (and possibly other PFAS chemicals) either later this year or early in 2023. While its LHA’s suggest that EPA is targeting MCLs approaching zero, it will be interesting to see whether the ACC’s legal challenge and WHO’s new draft guidance alters EPA’s decision-making. Those regulatory decisions will have a tremendous impact on the economy, as MCLs approaching zero could force most, if not all, water providers to remediate PFAS, who may then look to litigation to recover those costs. As such, it is important for water suppliers and other stakeholders to closely monitor the ACC’s legal challenge and EPA’s MCL regulatory actions in order to adequately prepare to meet future regulatory requirements and the potential exorbitant costs that may be associated with compliance, as well as to stay abreast of potential opportunities to challenge any such regulatory action.