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December 1, 2016

EPA Publishes a TSCA "Top 10" List of Sorts: What Chemicals Made the Cut?


EPA has successfully met one of the first major milestone of the Agency's First Year Implementation Plan for the Frank R. Lautenberg Chemical Safety for the 21st Century Act. On November 29, 2016, EPA published its initial list of 10 "high priority" chemical substances from its 2014 Update to the Work Plan for Chemical Assessments (i.e., "Work Plan Chemicals") that will undergo risk evaluations under deadlines established by the 2016 amendments to the Toxic Substances Control Act (TSCA). The substances EPA listed are:


Methylene Chloride




Pigment Violet 29

Carbon Tetrachloride

Tetrachloroethylene or perchloroethylene

Cyclic Aliphatic Bromide Cluster



Some years prior to the 2016 amendments to TSCA, EPA had embarked on a plan to identify and review information concerning the health and environmental effects of chemical substances in use in the US. Ultimately, the Agency intended to assess the risks presented by the substances and, depending on the outcome of the assessments, take regulatory actions as appropriate. In doing so, EPA hoped to shake-off the widely-held perception that the Agency could not effectively review and regulate chemicals under the 40-year-old legislation. Thus, EPA had unveiled its initial sorting and prioritization method and subsequently identified a set of "Work Plan" chemicals for further assessment. The Work Plan list was originally released in 2012 and was updated in 2014. Some of the criteria important to EPA in selecting chemicals for the Work Plan included: potential to be of concern to children's health; neurotoxicity; persistence, bioaccumulation, and toxicity (PBT); carcinogenicity; use in children's products; and detection in biomonitoring programs or in drinking water.

In the 2016 amendments to TSCA Congress acknowledged and accommodated the Agency's progress to date on developing the Work Plan list while at the same time imposing additional requirements that EPA must eventually prioritize all substances that are actively in commerce and undertake risk evaluations for those substances which "may present an unreasonable risk" to health or the environment. Under Section 6(b)(1)(A) of the amended TSCA, EPA is to consider a number of factors in prioritizing chemicals as either "high" or "low" priority:

The process to designate the priority of chemical substances shall include a consideration of the hazard and exposure potential of a chemical substance or a category of chemical substances (including consideration of persistence and bioaccumulation, potentially exposed or susceptible subpopulations and storage near significant sources of drinking water), the conditions of use or significant changes in the conditions of use of the chemical substance, and the volume or significant changes in the volume of the chemical substance manufactured or processed. (emphasis added)

The amended law defines "high-priority" substances as those that "may present an unreasonable risk of injury to health or the environment because of a potential hazard and a potential route of exposure ... including an unreasonable risk to a potentially exposed or susceptible subpopulation" (e.g., infants, children, pregnant women, workers, or the elderly). Section 6(b)(1)(B)(i).

In accordance with additional guidance in the Act, EPA has stated its intent to accord preference to those substances with persistence and bioaccumulation scores of 3 (using EPA's Work Plan chemicals scoring system), and known human carcinogens with high acute or chronic toxicity.1 Ultimately, the statute requires that 50% of the high priority chemicals selected for risk evaluations must come from the 2014 Work Plan, until the approximately 90-chemicals list is depleted. Among other near-term priorities for the Agency, EPA must issue by June 2017 final procedural regulations that will address how future prioritization exercises will be conducted, and how its risk evaluation process will be managed.2

EPA's "High Priority" List Contains Few Surprises

Many of the substances on EPA's initial list of "high priority" substances come as no surprise. At the time of the TSCA amendments, EPA had already initiated risk assessments for approximately a dozen Work Plan substances and EPA has selected five of its first 10 "high priority" substances from the shorter list of those substances for which EPA has completed risk assessments: 1-Bromopropane, 1,4-Dioxane, Methylene Chloride, and N-Methylpyrrolidone (NMP), Trichloroethylene (TCE). Both 1-Bromopropane and 1,4-Dioxane were likely candidates, because they have a hazard score of 3, are possible carcinogens, are widely used in consumer products, have high reported releases to the environment, and have been detected in drinking water or groundwater. In contrast, Methylene Chloride and NMP, which have both low environmental persistence and potential for bioaccumulation, were less likely choices—especially considering that EPA recently submitted proposed regulations to OMB for review that will likely propose limits on certain uses of those two substances pursuant to Section 6(a) of TSCA. EPA choice of trichloroethylene (TCE) is similarly somewhat surprising, given that EPA has also undertaken a rulemaking with respect to TCE under TSCA Section 6(a) and the Notice of Proposed Rulemaking has been under review at OMB for some time and is projected to be published in the Federal Register in December. This strongly suggests there are uses for these thee substances that remain of concern to EPA and that fall outside of the scope of the proposed rules EPA already has submitted to OMB for review. It also might be the case that Agency officials, in view of the impending change of Administrations, want to provide some "insurance" through these particular listings and provide the additional momentum that can be leveraged by NGOs who can point to the new statutory deadlines should the pending proposals get stalled (or derailed) along the way.

Carbon tetrachloride is a listing that is somewhat curious. Carbon tetrachloride has a hazard score of 3, is carcinogenic, was widely used in consumer products, has high reported releases to the environment, is highly persistent, and has been detected in drinking water supplies. Nevertheless, the major consumer uses in the US have largely ceased, maximum concentration limits have been established for drinking water, and there are workplace regulations governing its use and limiting worker exposures.

In contrast, EPA's selection of asbestos is not at all surprising, given that Senator Boxer (D-Calif) seemed willing to torpedo the TSCA amendments because asbestos was not singled out by name in the legislation at the time when the amendments were coming up for a vote in the Senate. The asbestos listing also provides the Agency the perfect opportunity to truly test whether the recent amendments to the statute will finally enable EPA to more readily address a substance that was the target of restrictions in a TSCA Section 6 rulemaking that was successfully challenged in federal court a quarter century ago.3

EPA's choice of the Cyclic Aliphatic Bromides Cluster of substances is also no surprise. These substances are among a number of flame retardant "clusters" of concern to EPA, this one including chemically- similar flame retardants such as Hexabromocyclododecane (HBCD). HBCB has a hazard score of 3, environmental persistence and a high potential for bioaccumulation and a history of use in consumer products with. EPA also published an Initial Assessment for this group of substances in August 2015.

Pigment Violet 29 and tetrachloroethylene are not unexpected choices given they both have properties that meet many—if not all—of the factors Congress set forth for selection to the "high priority" list. Pigment Violet 29 is widely used in consumer products, has high environmental persistence, toxicity to aquatic species, and hazard and exposure scores of 3. Tetrachloroethylene (PERC) has similar properties, is a probable human carcinogen and has also been detected in biomonitoring programs and in drinking water supplies.

EPA's "High Priority" List Partially In Line With What NGOs Had Proposed

Prior to EPA's announcement, several NGOs weighed in on what chemical substances EPA should slate for being among the first 10 identified for review. Safer Chemicals Healthy Families sent a letter to the EPA Administrator in August that recommended the following chemicals, of which the five listed in bold, below, made the cut:

Asbestos & Asbestos-like Fibers

Nonylphenol and Nonylphenol Ethoxylates (NP/NPEs)


Octamethylcyclotetrasiloxane (D4)

Cadmium & Cadmium Compounds



Tetrachloroethylene (PERC)

Lead & Lead Compounds

Hexabromocyclodecane (HBCD)

At least fifty other environmental, citizen, and special interest groups signed on to Safer Families' August 9, 2016 letter, including Earthjustice, Natural Resources Defense Council, Greenpeace, and United Steelworkers. Overall, the Safer Families' list was in tune with the factors listed in the amended Section 6 as prioritization considerations: All but one (D4) have a hazard score of 3; most are known or possible carcinogens; almost all are widely used in consumer products; all but one (1-Bromopropane) have moderate or high persistence in the environment or potential for bioaccumulation; many have been detected in drinking water supplies; and many have high reported (or estimated) releases to the environment.

Other NGOs weighed in as well, though not by presenting a formal list. The American Academy of Pediatrics submitted a comment to EPA's Docket for the risk prioritization process procedural rule that identified "examples" of three substances that may merit "high priority" status under the new law, including Lead, PFAS, and phthalates (e.g., DEHP, DBP, and BBP). The Silent Spring Institute, focused on women's health, also submitted comments to EPA's Dockets for both upcoming procedural rules (for risk prioritization and evaluation), and singled out PFOA and perfluorinated chemicals (PFCs) as suspected mammary gland carcinogens that warranted further scrutiny by EPA. The Environmental Defense Fund in a comment it submitted regarding the risk prioritization rule also drew attention to PFOA as a bioaccumulative chemical of concern that would not fall under the law’s expedited review for PBTs. Although EPA itself has expressed concern about PFCs,4 the Agency announced in 2014 that this group of substances would not be included in the Work Plan list because it had already undertaken certain risk-management actions for PFCs.5 Thus, it is no surprise that the category was absent from the first 10 "high priority" substances list.

Some Candidates That Didn't Make The Cut

Of the 90 substances that appear in EPA's 2014 Work Plan Update, there are several that met many of the prioritization factors laid out in the amended law, but did not make the final "top 10" list. Some of these substances appear on the Safer Families list as noted above; others include the following.

Arsenic & Arsenic Compounds

Cyanide Compounds

Di-isodecyl phthalate (DIDP)


Phenol, isopropylated phosphate (3:1) (iPTPP)

Vinyl Chloride

Arsenic should score highly under the prioritization process rule EPA has yet to propose, but nevertheless must finalize by June of next year: It has a hazard score of 3, is carcinogenic, is widely used in consumer products, has high reported releases to the environment, is highly persistent, and has been detected in drinking water supplies. DIDP is among a cluster of phthalates EPA considered to be "Action Plan" chemicals that were migrated into the Work Plan list in 2014. Thus, DIDP (alone or with the other phthalates in the grouping), would have been another likely candidate for prioritization under the amended law, due to its hazard score of 3, developmental toxicity, and reports that it is in widespread use in anything from manufacturing to cosmetics and medical supplies. Flame retardants like iPTPP were added to the Work Plan in 2014 and were another likely candidate for the initial group prioritized for risk evaluation. iPTPP is listed in the Work Plan as having neurotoxicity and high persistence and high potential for bioaccumulation in the environment. TPP is another flame retardant added to the Work Plan in 2014 and believed to be in use in children's products. These substances and groupings will likely remain as candidates from which EPA might select when it seeks to ensure it has a total of 20 substances undergoing risk evaluations by the end of 2019.

Important Next Steps for EPA

Within 6 months of the recent announcement (by June 2017), EPA also must publish the scope of each of the first 10 risk assessments, which will then be subject to a public comment period. The "scoping document" for each substance or cluster will include the hazards, exposures, conditions of use, and the potentially exposed or susceptible subpopulations the Agency plans to consider in the risk evaluation. These risk evaluations eventually will determine whether a substance present an "unreasonable risk" in the context of the intended conditions of use and any reasonably foreseeable uses. The amended law requires the Agency to complete these risk evaluations within three years. If the evaluation prompts the Agency to determine that a chemical substance presents an unreasonable risk under certain use conditions, EPA must undertake and complete a Section 6 rulemaking within two years (unless an extension of as much as two additional years is needed).

On a parallel path, EPA must issue within three years proposed TSCA Section 6 regulations concerning 5 recently identified "high priority PBTs." The proposed high-priority PBTs rules must reduce exposures "to the extent practicable." EPA must finalize the PBT rules within 18 months of proposal.6

Although the advent of the Trump Administration may not have an immediate effect on EPA's initial required milestones (such as publication of the upcoming risk evaluation "scoping documents"), it remains to be seen whether and when there will be some cooling effect on EPA's propensity (or resource capacity) to issue the numerous new Section 6(a) risk management actions that are required under the amended TSCA. Assuming EPA has the human resources and bandwidth to take on and meet these obligations, it is very unclear what kinds of risk management requirements a Trump-era EPA might be willing to impose.

  1. Public Meeting: Prioritization Procedural Rule at 7, August 10, 2016.

  2. For additional insight on those requirements and EPA’s First Year Implementation Plan, see our Advisory, "EPA Seeking Public Input on Procedural Rules Implementing 2016 TSCA Amendments."

  3. Corrosion Proof Fittings, et al., Petitioners, v. the Environmental Protection Agency and William K. Reilly, Administrator, Respondents, 947 F.2d 1201 (5th Cir. 1991)

  4. EPA, Assessing and Managing Chemicals under TSCA, Per- and Polyfluoroalkyl Substances (PFASs) under TSCA.

  5. EPA, "TSCA Work Plan for Chemical Assessments: 2014 Update" (October 2014).

  6. For an in-depth review of this requirement and the substances recently identified by EPA for such regulatory actions, see our recent article, "EPA Signals Intent To Exercise TSCA Section 6 Authority."