March 12, 2019

Emerging Contaminants: Coming to an NRD Site Near You!

Kristin Robrock and Sarah Bell

What Are Emerging Contaminants?

Emerging contaminants are chemicals in the environment for which the health risks—both human and ecological—remain unknown. They are also sometimes called contaminants of emerging concern, since the chemicals, or products containing such chemicals, may have been initially manufactured decades ago, though information about potential human health and/or ecological risks associated with such chemicals may only be emerging now. The U.S. Environmental Protection Agency (EPA) maintains a list of emerging contaminants. However, this list is not exhaustive and certain states consider other compounds as emerging contaminants as well.

A key criterion of all emerging contaminants is that they lack a federal maximum contaminant level (MCL) or other legally enforceable limit. Some emerging contaminants may have state MCLs, and most have some kind of established federal health goal. However, the lack of a federal standard creates a very discontinuous regulatory framework. Table 1 lists the compounds defined by EPA as emerging contaminants, and for each such compound, identifies the states (if any) that have enacted MCLs.

For those emerging contaminants that do not have enforceable regulatory standards, EPA and many individual states have established action levels or other non-enforceable guidelines. For example, EPA has issued drinking water health advisories for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). While these advisories can be given weight in litigation and regulatory proceedings, the 70 part-per-trillion (ppt) standard for PFOA and PFOS combined is not an enforceable limit. (Indeed, recent reports suggest that despite issuing an action plan for perfluorinated compounds, the EPA will not move quickly to establish drinking water limits for PFOA and PFOS, and for now these contaminants will remain unregulated under the Safe Drinking Water Act.

Table 1: Emerging contaminants listed by EPA, their use, and states that have implemented corresponding MCLs. The specific MCL is listed in parentheses. (Proposed MCLs are not listed.) ppb: parts per billion; ppt: parts per trillion

Emerging Contaminants and NRD Litigation

Several federal statutes provide for the recovery of natural resource damages (NRD), including the Clean Water Act; the Oil Pollution Act of 1990; the National Marine Sanctuaries Act; the Park System Resource Protection Act; and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), with most NRD actions arising under CERCLA. That said, many emerging contaminants, including perfluorinated chemicals such as PFOA and PFOS, are not yet listed as “hazardous substances” under CERCLA. Further, those few emerging contaminants that have been identified as “hazardous substances” under CERCLA, such as 1,4-dioxane, N-Nitroso-dimethylamine (NDMA), dinitrotoluene, and tungsten, still lack legally enforceable MCLs at the federal level.

As a result, many NRD sites and NRD cases in which emerging contaminants are at issue are sites and cases arising under state NRD statutes, rather than CERCLA or one of the other federal NRD statutes. Indeed, when it comes to regulating emerging contaminants, several states are ahead of EPA and the federal government. For example, California added PFOA and PFOS to its Proposition 65 list in 2017, with reproductive toxicity listed as the endpoint. New York State officially identified PFOA and PFOS as “hazardous substances” in 2016, and claims to have been the first state in the nation to do so. Vermont, New Hampshire, Michigan, Minnesota, and Alaska are among states that have also established cleanup levels for PFOA and PFOS, and New Jersey has developed MCLs for PFOA and perfluorononanoic acid (PFNA) in drinking water.

States are also leading the way in NRD litigation. In State of Minnesota v. 3M Company, No. 27-cv-10-28862 (Minn. D. Ct.), Minnesota’s attorney general filed an NRD suit on behalf of the state for damages for impacts from perfluorinated compounds pursuant to the Minnesota Environmental Response and Liability Act, which defines “hazardous substances” more broadly than CERCLA does. That litigation settled in February 2018 for $850 million. In addition, New Jersey’s January 2018 Report of the Environment and Energy Transition Advisory Committee (submitted to then Governor-elect Phil Murphy) specifically recommends that the state consider actively pursuing NRD actions for contamination from perfluorinated chemicals.

While CERCLA does not (yet) include PFOA or PFOS and certain other emerging contaminants as hazardous substances, the combination of state regulation of these compounds and state-based NRD statutes raises the likelihood that certain of these emerging contaminants will be identified at NRD sites. In fact, notwithstanding that CERCLA does not yet identify PFOA as a “hazardous substance,” EPA added the Saint-Gobain Performance Plastics Site in Hoosick Falls, New York, to the Superfund National Priorities List in 2017. The primary contaminants at issue there are PFOA and trichloroethylene. Furthermore, while EPA’s action plan for perfluorinated chemicals indicates that EPA has not yet started to establish drinking water limits for PFOA and PFOS, the EPA now reports that it has started the regulatory process to list PFOA and PFOS as “hazardous substances” under CERCLA. Given all these factors, it is not a stretch to imagine that federal trustees may initiate CERCLA NRD assessments at sites where perfluorinated compounds are at issue.

Looking Ahead: Which Emerging Contaminants Might Appear at Your NRD Site?

Despite the lack of certainty of the environmental or ecological impacts of these compounds, significant concerns surrounding some emerging contaminants have already made them the focus of some NRD assessments. As mentioned above, NRD claims have been brought for perfluorinated compound contamination in Minnesota (3M Cottage Grove), and NRD assessments have also been performed for perchlorate (e.g., Textron Systems/Mass Military Reservation, Massachusetts); 1,4-dioxane (e.g., Nuclear Metals Superfund site in Concord, Massachusetts, and the Hanford Site in Hanford, Washington); and polybrominated diphenyl ethers (e.g., Portland Harbor, Oregon, and Hudson River, New York).

To determine whether these examples are just anomalies or whether emerging contaminants are likely to become more prevalent at other NRD sites, we reviewed available occurrence data for these chemicals to determine which are more prevalent at sites across the country. Based on data from the third Unregulated Contaminant Monitoring Rule (UCMR 3), pursuant to which EPA mandates sampling of drinking water supplies for certain emerging contaminants,1,4-dioxane and perfluorinated compounds, including PFOS and PFOA, are widespread across U.S. drinking water supplies (Figure 1). In addition, UCMR 3 required sampling for 1,2,3-trichloropropane (TCP), which is also detected regionally in areas such as New York, Florida, and California. Data collected at Superfund sites indicates that 1,4-dioxane; 2,4,6-trinitrotoluene (TNT); and Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) have also been frequently detected at such sites.


Figure 1. Occurrence of 1,4-dioxane (left in orange) and perfluorinated compounds (including PFOS and PFOA) (right in green) in drinking water from UCMR3.

These findings are unsurprising. Perfluorinated compounds are associated with widely used commercial goods, including nonstick coatings, food container coatings, and fire-fighting materials (aqueous film-forming foams). Similarly, 1,4-dioxane is a solvent stabilizer and is thus often found at sites where there is contamination from chlorinated solvents. The explosives TNT and RDX are frequently found at former military sites.

In sum, certain of these emerging contaminants are widespread, particularly perfluorinated compounds. That, combined with state regulation of emerging contaminants perfluorinated compounds, state-specific NRD statutes that may already apply to emerging contaminants perfluorinated compounds, and EPA’s commencement of the regulatory process to define certain emerging contaminants (e.g., perfluorinated compounds) as “hazardous substances” under CERCLA, suggests that we should expect to find emerging contaminants perfluorinated compounds included in more NRD assessments, and that they may even become the main chemical driver at many NRD sites.

Looking Ahead: What’s Looming in Emerging Contaminants?

The 1996 amendments to the Safe Drinking Water Act included development of the UCMR, a program that requires EPA—every five years—to list up to 30 unregulated contaminants to be monitored by public water systems. The 2012 UCMR required monitoring from 2013 to 2015 of 28 chemicals and two viruses, including many of the emerging contaminants that are the focus of this article, including PFOA, and 1,4-dioxane. (It is likely no surprise that now we are seeing heightened awareness and focus on regulation of perfluorinated compounds, including PFOA, given that PFOA was identified in the 2012 UCMR.)

The more recent 2016 UCMR (UCMR 4) requires monitoring for 30 compounds from 2018 to 2020, including cyanotoxins, haloacetic acid (HHA), and several other metals and pesticides. The compounds identified in UCMR 4 may well be the emerging contaminants of tomorrow, and several years from now, we may see commentary on whether these UCMR 4 compounds should be the focus of NRD assessments.

    Kristin Robrock and Sarah Bell

    Published: March 12, 2019

    Dr. Kristin Robrock is an environmental engineer at Exponent in Oakland, California, who specializes in emerging contaminants, particularly flame retardants. She focuses on fate and transport of chemicals in the environment and forensic investigations, reconstructing environmental releases to determine the sources, timing, and mechanisms of contaminant releases.


    Sarah P. Bell is a partner at Farella Braun + Martel LLP. She focuses her practice on environmental and natural resources litigation and counseling, including enforcement actions, cost recovery litigation, citizen suits, and water quality and complex toxic tort litigation. Her clients include product manufacturers and distributors, transportation companies, terminals, and commercial property owners.