Per- and polyfluoroalkyl substances, or PFAS, which are emerging contaminants known as “forever chemicals,” have become a hot topic in the environmental consulting world over the past few years.

Lawmakers have proposed bipartisan legislation, the PFAS Action Act of 2021, which is working its way through Congress. If passed, it would allow the U.S. Environmental Protection Agency (EPA) to establish timelines for making certain regulatory determinations regarding PFAS. It would also possibly include a requirement for the EPA to establish a national drinking water standard for various PFAS chemicals. Additionally, it could include a directive for the EPA to designate perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

This would trigger the remediation and treatment of PFAS released into the environment by providing consistent national standards as opposed to what is in place now — a patchwork of state-specific regulations.

PFAS regulations are changing just as rapidly as science's understanding of how PFAS behave in the environment. That means it is critical to include an evaluation of potential PFAS storage and usage at a site during the due diligence process.

Most environmental practitioners are aware that forever chemicals were used in products such as nonstick cookware, waterproofing materials and aqueous film-forming foam (AFFF). We are also learning these chemicals are associated with the aerospace, biotechnology, building and construction, metal plating, electronics, mining, and oil and gas industries, to name a few. These associations, and emerging PFAS regulations, can have far-reaching effects on the due diligence process, and the identification of potential environmental liabilities.

Due diligence is the skeleton or framework for building out the rest of the required environmental work at a site. When conducting due diligence, environmental professionals layer their understanding of a site’s current usage and history by combining a review of environmental records and historical imagery with knowledge of state-specific cleanup requirements to develop a fleshed-out conceptual site model (CSM).

An ASTM Phase I Environmental Site Assessment must meet the EPA requirements, which is known as the all appropriate inquiries (AAI). To do so, an environmental professional must have a comprehensive understanding of a site’s historical processes and how hazardous substances or petroleum products may have been used throughout the site’s history.

The ASTM Phase I Environmental Site Assessment standard does not list individual contaminants of concern that need to be included in the assessment. That is why, when considering a site, it is imperative to work with a knowledgeable environmental professional who is aware of the potential industries and products that PFAS may be associated with.

Other than the Lifetime Health Advisory limit of 70 nanograms per liter for PFOA, PFOS and combined PFOA/PFAS, the EPA has not yet established nationwide regulations or action levels for emerging contaminants. Since the EPA is not driving the regulations, individual states are taking actions to address public concerns while concurrently learning about the history and uses of PFAS.

The inclusion of PFAS in regulations and their associated action levels varies from state to state. Currently, approximately half of the states in the U.S. have regulations that address PFAS. If regulations at the state level are present, then the environmental professional needs to be aware of that state’s approach to PFAS to direct a property's due diligence conclusions and the subsequent site investigation and/or remediation.

If state-level PFAS regulations are not present, then the environmental professional still needs to include an evaluation for the presence of PFAS during the site’s due diligence process, even though no state approach to PFAS has been established. Either way, the environmental professional should include an evaluation for the presence of PFAS at a site during the due diligence process since state regulations are still in the early process of development and are subject to change.

To some, it may appear that direction is not being taken fast enough to cover how we approach PFAS in the future. But according to industry insiders, the EPA is methodically researching historical patents, known PFAS uses, and current environmental studies to compile a comprehensive list of all possible industries where PFAS can or could have been found. Not surprisingly, the list is longer than anyone ever thought possible.

PFAS have been a focus of public attention and regulation for several decades since the EPA expressed concern about the health consequences of these contaminants. Engineering and environmental consulting firms have a deep working knowledge of the industries and processes that involve PFAS and can provide meaningful insight to property owners as they navigate the world of these environmental hazards.

With proper guidance from a knowledgeable environmental team, including strategic remediation practitioners, industries faced with PFAS concerns can get the help needed to evaluate hard-to-identify PFAS risks and mitigate a wide range of potentially costly situations.


The importance of a thorough PFAS evaluation in the due diligence phase of a project cannot be underestimated. Addressing PFAS concerns at the outset of site development is key to saving time and money in the long run and can impact a project’s long-term success.

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Megan Desrosiers, PG, RPA, is a senior geologist and project manager for environmental remediation initiatives at Burns & McDonnell. She has more than 15 years of experience in environmental consulting and cultural resource management. She offers site characterization and remediation services and manages environmental site investigations of all scopes and sizes.