The U.S. Environmental Protection Agency (EPA) proposed on June 16, 2023, to ban most uses of perchloroethylene (PCE). 88 Fed. Reg. 39652. According to EPA’s June 8, 2023, press release, the proposed rule “would protect people from these risks by banning all consumer uses while allowing for many industrial/commercial uses to continue only where strict workplace controls could be implemented, including uses related to national security, aviation and other critical infrastructure, and the Agency’s efforts to combat the climate crisis.” EPA states that its proposed risk management rule “would rapidly phase down manufacturing, processing and distribution of PCE for all consumer uses and many industrial and commercial uses, most of which would be fully phased out in 24 months.” EPA notes that the uses subject to the proposed prohibitions represent less than 20 percent of the annual production volume of PCE. For most of the uses of PCE that EPA is proposing to prohibit, EPA’s analysis found that alternative products with similar costs and efficacy to PCE are “reasonably available.” Comments on the proposed rule are due August 15, 2023. EPA notes that under the Paperwork Reduction Act (PRA), “comments on the information collection provisions are best assured of consideration if the Office of Management and Budget (OMB) receives a copy of your comments on or before July 17, 2023.”

According to EPA’s web page on risk management for PCE, PCE “is a colorless liquid used primarily in industrial settings for the production of fluorinated compounds.” EPA notes that it is also used for dry cleaning, as a solvent for cleaning and degreasing, and in lubricants, adhesives, and sealants. EPA states that PCE has a limited number of consumer uses in products like adhesives for arts and crafts and stainless steel polish.

The proposed rule states that pursuant to Section 6(b) of the Toxic Substances Control Act (TSCA), EPA determined that PCE presents an unreasonable risk of injury to health, without consideration of costs or other nonrisk factors, including an unreasonable risk to potentially exposed or susceptible subpopulations (PESS) identified as relevant to the 2020 Risk Evaluation for PCE by EPA, under the conditions of use (COU). To address the unreasonable risk, EPA proposes, under TSCA Section 6(a), to:

• Prohibit most industrial and commercial uses and the manufacture (including import), processing, and distribution in commerce, of PCE for those uses;

• Prohibit the manufacture (including import), processing, and distribution in commerce of PCE for all consumer use;

• Prohibit the manufacture (including import), processing, distribution in commerce, and commercial use of PCE in dry cleaning and spot cleaning through a ten-year phaseout;

• Require strict workplace controls, including a PCE Workplace Chemical Protection Program (WCPP), which would include requirements to meet an inhalation exposure concentration limit and prevent direct dermal contact with PCE, for the 16 occupational COUs not prohibited;

• Require prescriptive workplace controls for laboratory use;

• Establish recordkeeping and downstream notification requirements; and

• Provide a ten-year time limited exemption under TSCA Section 6(g) for certain emergency uses of PCE in furtherance of National Aeronautics and Space Administration’s (NASA) mission, for specific COUs that are critical or essential and for which no technically and economically feasible safer alternative is available.

EPA notes that in addition, it proposes to amend the general provision of 40 C.F.R. Part 751, Subpart A, to define “authorized person,” “direct dermal contact,” “existing chemical exposure limit (ECEL),” “exposure group,” “owner or operator,” “potentially exposed person,” “regulated area,” and “retailer” so that these definitions may be commonly applied to this and other rules under TSCA Section 6 that would be codified under 40 C.F.R. Part 751.

EPA requests public comment on all aspects of the proposed rule, including the proposed and alternative regulatory actions and all individual elements of these, and all supporting analysis. Additionally, within the proposed rule, EPA includes more than 40 specific issues on which it requests comment. EPA states on its website that it will also host a webinar “in the coming weeks” about the proposed risk management rule.

Commentary

Bergeson & Campbell, P.C. (B&C^®) believes that EPA’s Office of Pollution Prevention and Toxics’ (OPPT) proposal appears to be reasonable except for two critical weaknesses: the ECEL and OPPT’s proposed ban for workplaces that can demonstrate compliance with the WCPP. We caveat that our “reasonable” determination is based on an assumption that OPPT complied with the legal requirements under TSCA and the implementing regulations, which we previously concluded that OPPT did not (See our memorandum dated July 12, 2022). We agree that banning consumer uses appears to be justified; however, there are outstanding legal and scientific issues that will likely be sources of contention between OPPT and regulated entities, including OPPT’s proposed ECELs, the methodology OPPT used for its review of alternatives, and OPPT’s decision to prohibit most industrial and commercial uses, regardless of whether a company can comply with the WCPP. Below, we have elaborated on these issues.

OPPT derived a chronic non-cancer ECEL of 0.14 ppm using a point of departure (POD) of 14.5 ppm and benchmark margin of exposure (MOE) of 100. The benchmark MOE consisted of a factor of 10× for intraspecies (i.e., human to human) uncertainty and 10× for lowest-observed-adverse-effect-concentration (LOAEC) to no-observed-adverse-effect-concentration (NOAEC) extrapolation uncertainty. We note that OPPT used the LOAEC-to-NOAEC approach when deriving the chronic non-cancer ECEL, rather than EPA’s preferred approach of using benchmark dose modeling to derive a POD referred to as the benchmark dose (BMD). B&C recognizes that not all data sets are amenable to BMD modeling; in our view, however, OPPT should present modeling results regardless of whether they are relied upon in an assessment. Transparency is vital in demonstrating that the best available science has been used. Without it, there is a danger that an Administration can select its preferred approach based on the desired outcome, rather than an approach that is based on the best available science.

OPPT stated that it “attempted to benchmark dose (BMD) model the results from [the two key studies used for deriving the ECEL],” but stated that “BMD modeling was not feasible for either study.” OPPT did not, however, provide the results of its BMD modeling outputs, as it did for other risk evaluations (e.g., 1-Bromopropane, Carbon Tetrachloride, Methylene Chloride, N-Methylpyrrolidone, and Trichloroethylene). In the end, EPA may be justified in not using the BMD approach, but EPA has not provided the scientific basis for its rejection of that approach.

OPPT relied on the Integrated Risk Information System’s (IRIS) cancer dose response modeling from 2008 for deriving its inhalation unit risk value and the associated lifetime cancer exposure limit (EL_cancer) of 0.47 ppm. We mention this because the scientific standards under TSCA Section 26(h) require use of the best available science, which includes methodologies and models. The version of the benchmark dose modeling software (BMDS) used by IRIS in 2008 is more than 14 years old. EPA has since released nine updated versions of BMDS from September 30, 2018, through March 2023, yet OPPT only provided BMD modeling results for cancer dose response modeling, as performed by IRIS in 2008. Again, the final limit may be close to one that is based on the best available science, but OPPT must recalculate the EL_cancer to fulfill the obligation under TSCA Section 26.

OPPT prepared an alternatives assessment on perchloroethylene and provided an extensive list of alternative products for most of the COUs. We note, however, that many of the identified alternative products were not sustainable or contained information contradictory to OPPT’s previous determinations. For example, several chemical substances undergoing risk evaluation and risk management are listed in the alternative products across COUs (e.g., 110 products with methylene chloride, Chemical Abstracts Service Registry Number (CAS RN^®) 75-09-2; 54 products with trichloroethylene, CAS RN 79-01-6; and 16 products with N-methylpyrrolidone, CAS RN 872-50-4). We also note that OPPT identified sodium gluconate (CAS RN 527-07-1) as a very high hazard concern for genotoxicity/mutagenicity; OPPT, however, did not complete the other human health hazard endpoint ratings for this substance. We mention this because OPPT designated sodium gluconate as a low-priority substance (LPS) under TSCA Section 6. OPPT’s scientific support document for the LPS designation included an evaluation of the available genotoxicity/mutagenicity studies on sodium gluconate, which OPPT concluded were negative (i.e., low hazard concern). These issues raise questions about OPPT’s methods for evaluating alternative products, given that comparable issues exist in OPPT’s alternatives assessments on chrysotile asbestos and methylene chloride.

For example, as we noted in our memorandum on OPPT’s proposed risk management rule on chrysotile asbestos, dated April 7, 2022, OPPT stated that it “believes an aggressive transition away from chrysotile asbestos will spur adoption of superior technology [e.g., membrane cells with increased concentrations of per- and polyfluoroalkyl substances (PFAS)].” EPA does not delve more deeply into the issue. Further, OPPT’s alternatives assessment on methylene chloride also identified alternative products that employ chemical substances undergoing TSCA risk management (e.g., N-methylpyrrolidone) or chemical substances slated for risk evaluation and potential risk management under TSCA (e.g., benzene and ethyl benzene). Based on these recurring issues, we question whether OPPT’s methodology for identifying alternative products would satisfy the scientific standards under TSCA Section 26.

The above issues underlie our concerns about OPPT’s proposal to prohibit most uses of perchloroethylene. TSCA Section 6(a) requires the Administrator to regulate existing chemical substances when OPPT determines that the chemical substance presents “an unreasonable risk of injury to health or the environment.” It further requires that risk mitigation measures be applied “to the extent necessary so that the chemical substance or mixture no longer presents such risk. [emphasis added]” As we discussed above, there are legal and scientific issues with OPPT’s proposed ECEL and OPPT’s alternatives assessment for perchloroethylene. In particular, we question OPPT’s proposal to prohibit COUs rather than allowing regulated entities to demonstrate their ability to comply with the WCPP. After all, OPPT determined that “as a matter of risk management policy that ensuring exposures remain at or below the ECEL will eliminate any unreasonable risk of injury to health from occupational inhalation exposures. [emphasis added]” If the WCPP addresses the unreasonable risk, the WCPP is the regulatory action that satisfies the TSCA Section 6(a) requirement to regulate “to the extent necessary” for workplace exposures. A ban on consumer uses would still appear to be justified since consumers are unlikely to be able to demonstrate compliance with the requirements of the WCPP. Similarly, to the extent that EPA identified risk to consumers from garments dry cleaned with PCE, EPA seems to have the facts to support a phaseout of its use in dry cleaning even if the employer can document compliance with the WCPP.

B&C applauds EPA’s proposal in the WCPP to require employers to inform employees in plain language in English and in the language of the largest group of workers who do not read English. EPA also appropriately prioritizes workplace protection strategies by encouraging engineering and administrative controls to meet the ECEL, with respiratory protection providing additional protection if exposures exceed the enforceable limit.

B&C encourages members of the regulated community to provide public comments on OPPT’s proposed rule on perchloroethylene, even if this substance is not in an entity’s supply chain. We recommend this because OPPT has shown that its preferred approach to regulating high-priority substances is an outright prohibition (i.e., ban) in addition to justifiable restrictions. Such a ban should only be needed for COUs in which the employer (or user) cannot document compliance with the WCPP, such as consumer uses. We expect that OPPT will apply this same approach to future existing chemical substances, given that OPPT has proposed bans in addition to workplace protection requirements for its two previous TSCA Section 6 rules (chrysotile asbestos and methylene chloride).