On October 30, 2023, EPA published a proposed rule altering the procedures for chemical risk evaluations under section 6 of the Toxic Substances Control Act (TSCA). The proposed rule revises the existing 2017 framework, which was adopted one year after Congress passed amendments to TSCA requiring EPA to evaluate whether existing chemicals that have been identified as “high priority” present an unreasonable risk of injury to health or the environment.

The rulemaking includes the following proposed changes:

• The clarification that EPA will include all conditions of use (i.e., circumstances under which the chemical is “intended, known, or reasonably foreseen to be manufactured, processed, distributed in commerce, used, or disposed of”) in the scope of a risk evaluation.
• The inclusion of all exposure pathways in the scope of a risk evaluation. EPA previously excluded exposure pathways covered under other EPA statutes in its risk evaluations for the first ten chemicals.
• The removal of the definitions for “best available science” and “weight of the scientific evidence.” Though TSCA requires EPA to use the best available science and make decisions based on the weight of the scientific evidence at 15 U.S.C. 2625, EPA argues that the codification of these definitions inhibits the Agency’s ability to adapt to changing science.
• The requirement that EPA make a single determination on whether the chemical presents an unreasonable risk. EPA initially made separate risk determinations for each condition of use in its risk evaluations for the first ten chemicals but later issued revised “whole substance” determinations.
• The cessation of the consideration of “assumed” personal protective equipment (PPE) use when calculating exposure reduction due to PPE.
• The addition of “overburdened communities” to the list of examples of potentially exposed or susceptible subpopulations.
• A number of alterations to the process and requirements for manufacturer-requested risk evaluations.

The above changes would apply to all risk evaluations initiated on or after the date of the final rule.  For risk evaluations in progress on the date of the final rule, EPA expects to apply the changes “only to the extent practicable.”

The proposed clarification that EPA includes all conditions of use in the scope of a risk evaluation stems from the Ninth Circuit’s 2019 decision in Safer Chemicals, Healthy Families v. EPA. In the case, petitioners successfully challenged EPA’s exclusion of “legacy uses and associated disposals”—such as the use and future disposal of asbestos in previously installed insulation—from the scope of risk evaluations. Several of the other proposed changes would codify existing EPA practices introduced in 2021, including the requirement that risk evaluations end with a single determination rather than use-by-use determinations.

EPA requests public comments on all aspects of the proposed rulemaking. Comments are due on December 14, 2023.

On April 20, 2023, EPA released a proposed rule under Section 6(a) of the Toxic Substances Control Act (“TSCA”) that would drastically limit the use of methylene chloride. Section 6(a) of the statute provides EPA authority to ban or restrict the manufacture, processing, distribution, and use of chemical substances that pose an unreasonable risk of injury to human health or the environment. EPA explains that its decision is driven by concerns about the risks posed to workers, occupational non-users, consumers, and individuals in close proximity to consumer usage. The Agency stated that it is particularly concerned about adverse health effects such as neurotoxicity, liver damage, and cancer resulting from inhalation and dermal exposure to methylene chloride.

EPA’s proposed rule seeks to “rapidly phase down” the manufacturing, processing, and distribution of methylene chloride for consumer use, as well as most industrial and commercial uses. The phase down is expected to be completed within 15 months of the effective date of the final rule. EPA’s analysis indicates that alternative products with similar cost and effectiveness to methylene chloride are generally available for most of the that the Agency intends to prohibit.

According to EPA, methylene chloride poses an unreasonable health risk, without considering costs or other non-risk factors, including an unreasonable risk to potentially exposed or vulnerable subpopulations identified as relevant in the 2020 methylene chloride risk evaluation, under specific conditions of use (“COU”). (EPA defines COU as the circumstances in which a chemical substance is intended, known, or reasonably foreseen to be manufactured, processed, distributed in commerce, used, or disposed of.) To address the unreasonable risk, EPA proposes the following restrictions:

• Prohibit the manufacture, processing, and distribution of methylene chloride for all consumer use.
• Prohibit most industrial and commercial uses of methylene chloride.
• Enforce a workplace chemical protection program (“WCPP”) that includes inhalation exposure concentration limits, workplace exposure monitoring, and exposure controls for ten specific conditions of use of methylene chloride.
• Require recordkeeping and downstream notification requirements for the manufacturing, processing, and distribution of methylene chloride in commerce.

The rule does provide an exemption to the prohibition on industrial uses for ten years for civilian aviation uses to prevent significant disruptions to critical infrastructure. This exemption will be subject to conditions such as compliance with the WCPP.  An exemption is also provided for emergency use of methylene chloride in support of the National Aeronautics and Space Administration’s mission. The exemption is limited to specific critical or essential conditions when no technically and economically feasible safer alternatives are available. This exemption will also require compliance with the WCPP. It too is time-limited to ten years.

EPA clarified that all COUs of methylene chloride under TSCA (except its use in consumer paint and coating removers, which was previously addressed under TSCA Section 6) will be covered by this proposal.

Regarding the WCPP for methylene chloride, EPA’s press release states that the agency collaborated with the Occupational Safety and Health Administration (OSHA) during the development of the proposed rule, taking into account existing OSHA requirements to ensure comprehensive worker protections. The Agency asserts that the proposed risk-based limits are based on up-to-date data and fulfill the TSCA mandate to eliminate unreasonable risks. If the rule is finalized, employers would have one year to comply with the WCPP and would be obligated to periodically monitor the workplace to ensure that workers are not exposed to methylene chloride at levels that pose an unreasonable risk.

In the Federal Register notice, EPA particularly requested comments on the feasibility and effectiveness of the proposed worker protection requirements from parties that would be responsible for implementing the program. (The comment period closed on July 3.) Additionally, EPA hosted a public webinar on June 7 to present overview of the proposed regulatory action and provide an opportunity for participation in discussion on the proposed WCCP. Materials from the webinar are available on EPA’s website.

EPA recently released two documents regarding cumulative risk assessments under TSCA section 6, Draft Proposed Principles of Cumulative Risk Assessment Under the Toxic Substances Control Act, and Draft Proposed Approach for Cumulative Risk Assessment of High-priority Phthalates and Manufacturer-Requested Phthalate under the Toxic Substances Control Act. The first document details a set of principles for evaluating the cumulative risk of substances under TSCA; the second document presents a proposed approach for applying those principles to the evaluation of the cumulative risk posed by certain phthalate chemicals which are currently undergoing TSCA section 6 risk evaluation.

In the  Draft Proposed Principles of Cumulative Risk Assessment Under TSCA, EPA explained that it plans to alter its approach to individual substance evaluations under TSCA section 6 by taking a cumulative assessment approach when appropriate. Previously, the Agency looked at the risks posed by a single substance under its specific conditions of use. The Agency now intends to implement a new approach to evaluating human health effects, which it believes is more appropriate when considering human exposure to these substances. People are often exposed to many chemical substances with similar effects at the same time, and looking at the combined exposure health risk will paint a more complete picture. The Agency believes that this approach will allow for more effective mitigation of identified unreasonable risks and provide particularly useful information for communities that face higher than normal levels of chemical pollution.

Phthalates will be subjected to a cumulative risk assessment because the group of substances has similar effects on human health and has generally been found concurrently in the human body. The phthalates to be assessed as a group include DEHP, BBP, DBP, DIBP, DCHP, DINP, and DIDP. The chemical group is often used in industrial and consumer products to make plastics more flexible and durable. The draft proposal requests comment and peer review on its assessment that six phthalate substances are toxicologically similar, and the U.S. population is frequently co-exposed to these substances, making a cumulative risk assessment the most appropriate course of review action under TSCA.

The Agency is accepting comments on these documents through April 28, 2023.