The U.S. Environmental Protection Agency (EPA) published on March 26, 2024, a proposed rule requiring manufacturers (including importers) of 16 chemical substances to submit copies and lists of certain unpublished health and safety studies to EPA. 89 Fed. Reg. 20918. EPA identified 15 of the chemical substances as potential candidates for prioritization through a screening process based on a combination of hazard, exposure (including uses), and persistence and bioaccumulation characteristics. EPA also included the N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) transformation product 2-anilino-5-[(4-methylpentan-2-yl) amino]cyclohexa-2,5-diene-1,4-dione (6PPD-quinone) due to a response to a recent citizen’s petition filed under Section 21 of the Toxic Substances Control Act (TSCA) on 6PPD and 6PPD-quinone. According to the proposed rule, health and safety studies sought by this action will help inform EPA’s responsibilities pursuant to TSCA, including prioritization, risk evaluation, and risk management. Comments are due May 28, 2024.

Chemical substances for which health and safety study data reporting is required are listed at 40 C.F.R. Section 716.120. For this proposed rule, the 16 chemical substances will amend the current list and be added at 40 C.F.R. Section 716.21(a)(11). The chemical substances being added by this proposed rule are:

• 4,4-Methylene bis(2-chloraniline) (Chemical Abstracts Service Registry Number^® (CAS RN^®) 101-14-4);
• 4-tert-octylphenol(4-(1,1,3,3-Tetramethylbutyl)-phenol) (CAS RN 140-66-9);
• Acetaldehyde (CAS RN 75-07-0);
• Acrylonitrile (CAS RN 107-13-1);
• Benzenamine (CAS RN 62-53-3);
• Benzene (CAS RN 71-43-2);
• Bisphenol A (CAS RN 80-05-7);
• Ethylbenzene (CAS RN 100-41-4);
• Naphthalene (CAS RN 91-20-3);
• Vinyl Chloride (CAS RN 75-01-4);
• Styrene (CAS RN 100-42-5);
• Tribromomethane (Bromoform) (CAS RN 75-25-2);
• Triglycidyl isocyanurate (CAS RN 2451-62-9);
• Hydrogen fluoride (CAS RN 7664-39-3);
• 6PPD (CAS RN 793-24-8); and
• 6PPD-quinone (CAS RN 2754428-18-5).

The proposed reporting requirements include:

• Manufacturers who, in the ten years preceding the date a chemical substance is listed, either have proposed to manufacture or have manufactured any of the listed chemical substances must submit to EPA, during the 60-day reporting period specified in 40 C.F.R. Section 716.65 and according to the reporting schedule set forth at 40 C.F.R. Section 716.60, a copy of each specified type of health and safety study that is in their possession at the time the chemical substance is listed in 40 C.F.R. Part 716.
• Manufacturers who, either at the time of or after the chemical substance is listed in Part 716, propose to manufacture or are manufacturing the listed chemical substance would be required to submit to EPA during the 60-day reporting period specified in 40 C.F.R. Section 716.65 and according to the reporting schedule set forth at 40 .C.F.R. Section 716.60:
  • A copy of each specified type of health and safety study that is in their possession at the time the chemical substance is listed;
  • A list of the specified types of health and safety studies known to them but not in their possession at the time the chemical substance is listed;
  • A list of the specified types of health and safety studies that are ongoing at the time the chemical substance is listed and are being conducted by or for them;
  • A list of the specified types of health and safety studies that are initiated after the date the chemical substance is listed and will be conducted by or for them; and
  • A copy of each specified type of health and safety study that was previously listed as ongoing or subsequently initiated and is now complete regardless of completion date.

EPA proposes that the exemption listed at 40 C.F.R. Section 716.20(a)(9), for persons manufacturing a substance only as an impurity, would not be available for the substances subject to this proposed rule. EPA states that rulemaking proceedings that add chemical substances and mixtures to 40 C.F.R. Section 716.120 will specify the types of health and safety studies that must be reported and will specify the chemical grade/purity that must be met or exceeded in individual studies. Pursuant to the rulemaking procedure that requires EPA to identify the chemical/grade purity, EPA “is requiring reporting on any purity level of the chemical.”

EPA proposes to require submissions of health and safety studies from companies manufacturing the identified chemical substances, including when a company is importing the chemical substance as a pure substance, mixture, formulated product, or article containing the subject chemical substance. Reporting would be required where the chemical substance is included as an impurity. EPA states that it “considers conditions of use [(COU)] associated with circumstances where a chemical substance subject to a risk evaluation even where the chemical substance is an impurity.” To such ends, according to EPA, health and safety information associated with the COUs, whether as a pure chemical, part of a mixture or article, or as an impurity, helps inform such risk evaluation.

Pursuant to 40 C.F.R. Sections 716.10 and 716.50, manufacturers are required to submit the following types of information:

• Lists and copies of unpublished health and safety studies for all substances specified in this rule on health effects, such as toxicity studies (e.g., in vivo, in vitro) on carcinogenicity, reproductive and developmental effects, genotoxicity, neurotoxicity, immunotoxicity, endocrine effects, and other systemic toxicity and toxicokinetic (absorption, distribution, metabolism, or elimination), including modeling studies, in humans or animals.
• All unpublished studies on environmental effects and physical-chemical properties if performed as described in 40 C.F.R. Section 716.50.
• All unpublished studies on occupational, general population, consumer, and environmental exposure, such as: unpublished studies on inhalation and dermal exposure, human biomonitoring, environmental monitoring of indoor and outdoor air, soil, water, and household dust, chamber emission rates from products or polymeric matrices, and unpublished modeling studies that estimate environmental concentrations or human exposures.
• Studies showing any measurable content of the tested substance (single substance or mixture). The composition and purity of test substances must be reported if included as part of the study.
• Studies previously submitted to EPA pursuant to a requirement under TSCA or of the submitter’s own accord and studies conducted or to be conducted pursuant to a TSCA Section 4 action are exempt from the submission of lists of health and safety studies required under 40 C.F.R. Section 716.35 and the submission of studies required under this rule.
• Surveys, tests, and studies of biological, photochemical, and chemical degradation.

EPA notes that chemical identities are part of the submitted health and safety studies or data and must be submitted to EPA. EPA states that “[i]nformation from health and safety studies and/or data is not protected from disclosure, except to the extent such studies or information reveal information ‘that discloses processes used in the manufacturing or processing of a chemical substance. Or, in the case of a mixture, the portion of the mixture comprised by any of the chemical substances in the mixture.’” 15 U.S.C. § 2613(2)(B). Additional information, listed in the rule’s definition of health and safety study, is not part of a health and safety study (e.g., names of laboratory personnel). Submitters asserting a confidential business information (CBI) claim for information are required to submit a sanitized copy, removing only the information that is claimed as CBI.

Commentary

The Acta Group (Acta®) is pleased to see EPA utilizing its information gathering authorities to inform its potential risk evaluation activities under TSCA Section 6. EPA has the authority to issue the data call-in and arguably must do so to fulfill its obligation on “reasonably available information.” That said, we have two concerns with this rulemaking: one is the timing (issuing a data call-in after initiating prioritization) and the other is the lack of an exemption for studies in which the substances are present as an impurity.

On December 18, 2023, EPA announced it was beginning the process to prioritize acetaldehyde, acrylonitrile, benzenamine, 4,4’-methylene bis(2-chloroaniline) (MBOCA), and vinyl chloride as high-priority substances (HPS) under TSCA. The public comment deadline for this announcement was March 18, 2024. For discussion, see our memorandum dated December 28, 2023. Our view is that EPA could optimize the utility of this authority more effectively by issuing the TSCA Section 8(d) data call-in for these substances prior to initiating prioritization. This way, EPA could better ensure it is able to review existing information in advance of prioritizing a substance. We recognize that EPA has practical considerations for initiating prioritization for the five chemical substances and we expect that EPA will use the TSCA Section 8(d) data to inform prioritization of the other 11 substances subject to this rule. Ideally, in the future, EPA will issue data call-in rules to inform prioritization.

Our main concern, as discussed below, is EPA’s decision not to include a de minimis level of the substances potentially subject to the proposed TSCA Section 8(d) rule.

If EPA maintains a similar timeline for the five chemical substances as it did for its prioritization in March 2019 of the “Next 20,” we expect that EPA will announce its proposed HPS designations for the five chemical substances around the end of May 2024. This will follow with a mandatory 90-day public comment period with EPA’s final HPS designations being announced around 30 days later, the end of September 2024. In comparison, if we assume that EPA issued the final TSCA Section 8(d) rule within 30 to 60 days after the close of the public comment period, the effective date of the rule will be 30 days thereafter (around the end of July or August 2024). Regulated entities will then have 60 days to report health and safety studies (around the end of September or October 2024).

This timeline will mean that the HPS designation for the five substances will precede EPA’s receipt of the TSCA Section 8(d) data call-in. EPA will then undertake a data adequacy review of those studies; such a review could take an additional four months based on the length of the review of the results of the 2011 test rule for High-Production Volume (HPV) substances (which coincidentally included acetaldehyde and aniline (benzenamine)). While EPA will have the data to inform risk evaluation, EPA will have missed the opportunity to use these data in its prioritization. As noted, we hope this will be the last time EPA will issue a TSCA Section 8(d) rule after initiating the prioritization process. Rather, we expect that EPA will issue a TSCA Section 8(d) rule for batches of chemical substances that EPA will expect to consider for prioritization well in advance of initiating the prioritization process.

EPA’s announcements on the proposed five chemical substances undergoing its prioritization process and the proposed TSCA Section 8(d) rule provide an indication of EPA’s fiscal year 2026 (October 1, 2025 – September 30, 2026) and 2027 (October 1, 2026 – September 30, 2027) priorities. For example, EPA stated that:

[It] generally expects to complete five risk evaluations per year over the next several years, EPA is initiating the prioritization process for five chemical substances per TSCA section 6(b)(3)(C), which requires EPA to designate at least one High-Priority Substance upon completion of each risk evaluation for a High-Priority Substance.

It is likely that the remaining ten (counting 6PPD and its degradant as one) chemical substances will undergo EPA’s prioritization process in the next two years.

More important than the temporal issues noted above, EPA did not state a threshold concentration for the chemical substances in the requested health and safety studies. For example, EPA stated that:

[It] is proposing that the exemption listed at 40 CFR 716.20(a)(9), for persons manufacturing a substance only as an impurity, would not be available for the substances subject to this proposed rule.

We mention this because EPA has previously established reporting thresholds, as it did in the TSCA Section 8(a) reporting and recordkeeping rule on nanoscale materials, that included a “numerical value of less than 1% of particles from 1-100 nm by weight to define those chemical substances that are not reportable.” It is not clear to us how EPA will interpret studies in which one of the TSCA Section 8(d) substances is present at low levels. How will EPA attribute observed adverse effects in such studies? Will EPA assign an adverse effect to the impurity and extrapolate a point of departure to the impurity substance when neat? Or will EPA attempt to partition observed effects between and among the test substances as impurities? Our view is that EPA should focus on studies conducted on the target substance, so that EPA can better distinguish between effects on the substance and effects from substances in which the target substance may be an impurity. Our reading of 40 C.F.R. Section 716.20(b)(5) that requires EPA to “specify the chemical grade/purity requirements that must be met or exceeded in individual studies” is meant to ensure EPA is considering whether a TSCA Section 8(d) substance being present below a specified threshold will be useful in informing a toxicity assessment for that substance. That is to say, if a test material is only 75 percent of that material, is that sufficiently pure to inform meaningfully a hazard assessment? In this rule, EPA seems to be stating that the threshold should be zero — that any amount, even parts per billion, is “useful.” If that is the interpretation, we respectfully disagree. By including studies that include any amount of these substances, EPA vastly expands the universe of studies that must be considered — arguably every toxicity study ever performed is potentially responsive because any of these substances could be present. EPA may also be underestimating the cost of reviewing records, as it did with the TSCA Section 8(a)(7) reporting rule, in determining the cost of how a company assesses whether it has responsive records. EPA’s estimates focus only on the cost of submitting responsive records, and not reviewing all studies that may contain trivial amounts of these chemicals as an impurity.

Acta encourages interested parties to submit public comments on EPA’s proposed TSCA Section 8(d) rule, as appropriate, both in terms of the timing of the TSCA Section 8(d) rule relative to prioritization and, more importantly, whether a content threshold is appropriate.