EPA’s Signal Intent to Move Forward with MCL Process for PFAS


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EPA’s Signal Intent to Move Forward with MCL Process for PFAS

By: George Colvin, CPG, CHMM

On February 14, 2019, US EPA (EPA) announced the release of its per-and polyfluoralkyl substances (PFAS) action plan.  Consistent with the Administration’s first ever, best-ever marketing approach, the PFAS Action Plan is billed by Assistant Administrator David Ross (in his February 15 letter to Senator Thomas Carper) as the “first-ever PFAS Action Plan.”   The Action Plan describes EPA’s approach to identifying and understanding PFAS, addressing current PFAS contamination, preventing further contamination, and communicating with the public.  

The term PFAS refers to per-and polyfluoroalkyl substances. PFAS are a very large group of synthetic chemicals that have been used in a wide variety of consumer and industrial products since the 1940s.  Due to their widespread use and persistence in the environment, they are commonly found in human blood samples.  Current information suggests that continued exposure above specific levels to certain PFAS may lead to adverse health effects.  In 2016, EPA released lifetime drinking water Health Advisories for perfluorooctanoic acid (PFOA) and perfluoroctane sulfonate (PFOS), two of the chemicals in the PFAS family.  Health Advisories are non-enforceable and non-regulatory and provide technical information to state agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination. EPA first announced that it would be initiating steps to evaluate the need for a maximum contaminant level (MCL) for PFOA and PFOS in drinking water during the May 2018 EPA PFAS National Leadership Summit, and its decision on this has been highly anticipated.   

Unfortunately for some, EPA’s position as reflected in the Action Plan is not as clear as it could be, stating that “The EPA is committed to proposing a regulatory determination for PFOA and PFOS.” Committing to proposing a regulatory determination does not necessarily mean that EPA will promulgate an MCL.  The Safe Drinking Water Act (SDWA) requires EPA to consider the following three criteria when making a determination to regulate:

  • The contaminant may have an adverse effect on the health of persons
  • The contaminant is known to occur or there is a high chance that the contaminant will occur in public water systems often enough and at levels of public health concern
  • In the sole judgment of the Administrator, regulation of the contaminant presents a meaningful opportunity for health risk reductions for persons served by public water systems

When making the determination, EPA first publishes a preliminary regulatory determination in the Federal Register (FR) and provides an opportunity for public comment. After review and consideration of public comment, EPA publishes a final FR notice with the regulatory determination decisions. If EPA makes a decision to regulate a particular contaminant, the Agency starts the rulemaking process to establish the national primary drinking water regulation. It is entirely possible that the Agency may decide not to regulate a particular contaminant based on the three criteria.  For instance, in 2016 EPA announced the final determination not to regulate four contaminants on the third drinking water contaminant candidate list (CCL3) including dimethoate, 1,3-dinitrobenzene, terbufos, and terbufos sulfone.  

During the February 14, 2019 press conference announcing the Action Plan, when asked if it was possible that the determination may result in not setting an MCL, EPA Acting Administrator Andrew Wheeler answered “… we have, I have every intention of setting an MCL.” In a February 15, 2019 letter to Senator Thomas Carper, EPA Assistant Administrator David Ross confirmed EPA’s position stating that “The EPA intends to establish a maximum contaminant level (MCL) for PFOA and PFOS” and that “EPA is committed to following the MCL rulemaking process.”  No time frame is given for establishing an MCL, however, the Action Plan states that EPA will propose a PFOA and PFOS regulatory determination for public comment in 2019.  

Assuming EPA makes the decision to regulate the contaminant in drinking water, the agency begins the rulemaking process to establish a national primary drinking water regulation.  After reviewing health effects data, EPA sets a maximum contaminant level goal (MCLG) for the chemical. MCLGs are non-enforceable public health goals. MCLGs consider only public health and not the limits of detection and treatment technology effectiveness. Therefore, they sometimes are set at levels which water systems cannot meet because of technological limitations. Once the MCLG is determined, EPA sets an enforceable standard. In most cases, the standard is an MCL. The MCL is the maximum level allowed of a contaminant in water which is delivered to any user of a public water system. It is set as close to the MCLG as feasible, taking costs into consideration, which can result in an MCL significantly higher than the MCLG.  When there is no reliable method that is economically and technically feasible to measure a contaminant at concentrations to indicate there is not a public health concern, EPA sets a “treatment technique” rather than an MCL. A treatment technique is an enforceable procedure or level of technological performance which public water systems must follow to ensure control of a contaminant. 

The decision to regulate and to develop a national primary drinking water regulation for a new contaminant is a big deal.  It does not happen often, and it will not happen overnight.  For this reason, as well as the general lack of federal leadership and commitment on the issue, several states including Pennsylvania are moving forward with their own MCL. In this era of de-regulation, we can be glad that there is a process which relies heavily on public involvement and can only hope that decisions are made based on the best science available.

Published in Cox-Colvin’s March 2019 Focus on the Environment newsletter.


George H. Colvin is a hydrogeologist with over 30 years of consulting experience. Much of his experience has focused on RCRA Corrective Action, RCRA closure, and groundwater investigation, monitoring, and cleanup. He holds a BS in Geology from Ohio University and MS in geology and hydrology from Vanderbilt University. He is a Certified Professional Geologist with the American Institute of Professional Geologists, a registered geologist in Kentucky, Pennsylvania, and Tennessee, and a Certified Hazardous Materials Manager.