1.1 Per- and polyfluoroalkyl substances (PFAS) are a group of over 7,000 manmade compounds consisting of polymeric chains of carbon bonded to fluorine atoms, usually with a polar functional group at the head. This guide recognizes that PFAS can be categorized as polymeric or nonpolymeric, collectively amounting to more than 4,700 Chemical Abstracts Service (CAS)-registered substances. Environmental concerns pertaining to PFAS are centered primarily on the perfluoroalkyl acids (PFAA), a subclass of per-and polyfluoroalkyl substances, which display extreme persistence and chain-length dependent bioaccumulation and adverse effects in biota.

1.2 The regulatory framework for PFAS continues to evolve, both domestically and internationally. The United States Environmental Protection Agency (EPA) is proceeding with a wide-ranging set of PFAS regulatory actions (EPA, 2021). While the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) does not currently recognize PFAS as hazardous substances, the statute does require actions to protect public health and the environment from contaminants and pollutants released to the environment. Other federal regulatory programs, such as the Safe Drinking Water Act are being used to address drinking water supplies adversely impacted by releases of PFAS. The Clean Water Act’s National Pollutant Discharge Elimination System (NPDES) permitting program is tool that both federal and state regulators are using to regulate the inflows of PFAS-impacted wastewaters at both publicly-owned treatment works (POTW) and federally-owned wastewater treatment plants and the concentration of PFAS in permitted effluent. EPA continues to add additional per-and polyfluoroalkyl substances to the list of substances reportable under the federal Toxic Release Inventory (TRI) reporting program. International efforts to address per-and polyfluoroalkyl substances include Australia’s PFAS National Environmental Management Plan, Version 2 (2020), Canada’s Prohibition of Certain Toxic Substances Regulations, (2022), the Stockholm Convention on Persistent Organic Pollutants, and the European Union’s Water Framework Directive (1).2

1.3 Hazardous waste treatment, storage, and disposal facilities (TSDF) currently operating under the Resource Conservation and Recovery Act (RCRA) via a Part B Permit may be ordered to investigate releases of PFAS under a RCRA Corrective Action order. EPA made a policy decision in the 1990s to defer many potential CERCLA enforcement actions to the RCRA Corrective Action Program (EPA, 1999). Permitted TSDFs at refineries may be subject to RCRA Corrective Action, as opposed to other regulatory programs, to address the releases of PFAS associated past and current use of aqueous film-forming foam (AFFF).

1.4 Numerous states and Tribes are using their existing regulatory programs to direct investigation, site remediation, and correction action related to releases of PFAS to soil, groundwater, and surface waters. These actions range from health advisories and guidelines to enforceable regulatory standards. Regulatory considerations include PFAS risks to both human health and ecological receptors that are protected under a broad array of federal, state, and tribal regulatory programs as well as by treaty rights.

1.5 This guide assists users in the identification of real property concerns that may be the source of PFAS releases or that may be adversely impacted by releases of PFAS. The goal of this guide is to assist managers of environmental risk in their resource allocation decision-making.

1.6 This guide does not constitute “All Appropriate Inquiries” as defined in 40 CFR Part 312 and is not intended to provide the user with any of the landowner liability protections codified in CERCLA §101(35)(A)(i), CERCLA §101(40)(B)(iii), or CERCLA §107(q)(1)(A)(viii)..

1.7 This guide describes widely accepted considerations and best practices used in the site screening and initial site characterization process, with specific consideration of the potential for the release of PFAS into the environment. This guide complements but does not replace existing technical guidance and regulatory requirements.

1.8 This guide does not address and is not applicable to sampling and analysis of public or private domestic water supply systems subject to regulation under the Safe Drinking Water Act and state private well testing act requirements. Regulatory agencies responsible for implementing the Safe Drinking Water Act may have established sampling and reporting requirements for public, community, and privately operated water systems.

1.9 All references to specific federal or state programs are current as of the date of publication. The user is cautioned not to rely on this guide alone but to consult directly with the appropriate program and legal counsel regarding this complex and rapidly evolving concern.

1.10 This guide is intended to complement, not replace, existing regulatory requirements or guidance. ASTM International (ASTM) guides are not regulations; they are consensus-based standards that may be followed as needed.

1.11 Units—The values stated in SI units are to be regarded as the standard. Other units, such as fractional units of parts per billion (ppb) and parts per trillion (ppt), are also included in this guide.

1.12 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.13 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.