California's Water Resource Control Board has issued statewide drinking water notification levels of 14 parts per trillion (ppt) for perfluorooctanoic acid (PFOA) and 13 ppt for perfluorooctanesulfonic acid (PFOS) directed at public drinking water systems (PWSs) throughout the state. The Water Board also set a response level for PFOA and PFOS at 70 ppt – matching the US EPA's health advisory levels (HALs).

The result of this July 13 action is that PWSs that voluntarily test for PFOA and PFOS must now report results that exceed the notification levels and, if the results exceed the response level, the Water Board will recommend that the supply well be taken offline.

PFOA and PFOS are part of a large group of manmade chemicals referred to as per- and poly-fluoroalkyl substances (PFASs). PFOS and PFOA have been extensively used in consumer products, firefighting foam and industrial processes. Both compounds have been phased out in the US and are now considered contaminants of emerging concern. California has yet to formally adopt the US EPA's HALs, nor has California promulgated maximum contaminant levels (MCLs) – legal limits on how much of a contaminant can be found in drinking water – for PFOA or PFOS.

By comparison, notification and response levels are non-regulatory and advisory only. In fact, they do not even require that PWSs test for PFOA or PFOS. Consequently, the levels' immediate impact on PWSs, including whether PWSs suffer any losses and whether we see an uptick in litigation as a result, is uncertain.

This development provides, however, an important look into the mind of California's Office of Environmental Health Hazard Assessment (OEHHA) concerning the direction in which OEHHA is leaning in the long-standing debate over the toxicity of PFOA and PFOS. OEHHA is the state's lead agency for the assessment of health risks posed by environmental contaminants and the state agency that establishes public health goals (PHGs) for contaminants, which are the cornerstone of MCLs. Thus, any position OEHHA takes on the toxicity of PFOA and PFOS will heavily influence California's eventual MCLs

To establish the notification levels, the Water Board had to first obtain a recommendation from OEHHA. OEHHA expressed its recommendations in a June 26, 2018 memorandum to the Water Board – a memo not widely publicized until the notification levels were announced on July 13. The memo details how, to assess the available toxicity studies for PFOA and PFOS, OEHHA reviewed and relied on the documents and process published by the State of New Jersey.

As we reported in December, New Jersey was the first state to formally set MCLs for PFOA at 14 ppt in drinking water and has made its work public and available to other states' agencies. Since then, New Jersey has established an advisory level for PFOS at 13 ppt. OEHHA, after reviewing what it describes as the "most recent comprehensive reviews that resulted in water advisory levels or standards for these chemicals," concluded that New Jersey's dose-response data for PFOA and PFOS is both "rigorous and sufficient for establishing interim NLs for these compounds." This signals that OEHHA considers New Jersey's levels – which are the toughest in the country – to be scientifically relevant and defensible interim advisory levels.

Additionally, the June memo moves MCLs a step further even than the establishment of notification levels. OEHHA qualifies its recommendation to the Water Board by stating that the current notification levels should be considered "interim" until OEHHA "completes its own derivation of recommended drinking water NLs for these chemicals," which is expected later this year. California Health and Safety Code requires the Water Board to establish MCLs at a level as close as is technically and economically feasible to the contaminants' PHG. A contaminant's PHG is the concentration in drinking water that does not pose any significant risk to health, derived from a human health risk assessment. In California, a contaminant's PHG is established by OEHHA. OEHHA's June memo indicates that it may be well on the way to establishing PHGs for PFOA and PFOS.

It is unknown whether OEHHA will announce PHGs for PFOA and PFOS this year. But, if PHGs are set and the Water Board moves forward with MCLs, it will have a tremendous impact – not only within the state, but for the nation. California's environmental policies are influential and typically on the leading edge of environmental rulemaking across the US. When OEHHA was pondering these actions, it looked to the work of New Jersey, as discussed above; similarly, work performed and conclusions reached by OEHHA concerning the toxicity of PFOA and PFOS will be scrutinized and likely relied upon by other states (and perhaps the US EPA).

Notably, in its June memo, referencing a recently published draft federal report, OEHHA concludes that "[a]pplying OEHHA's public health goal methodology to these [minimum risk levels established by ASTDR] would result in drinking water advisory levels of 13 ppt for PFOA and 9 ppt for PFOS."