EPA Bans Most Uses of Methylene Chloride

The U.S. Environmental Protection Agency (EPA) issued on May 8, 2024, a final rule under the Toxic Substances Control Act (TSCA) to address the unreasonable risk of injury to health presented by methylene chloride under its conditions of use (COU). To no one’s surprise, the EPA banned most uses of the chemical. However, surprisingly, the EPA also adopted a de minimis threshold to account for impurities and the unintended presence of methylene chloride. The final rule goes into effect July 8, 2024. Here is a summary.

Applicability

The final rule sets restrictions on the manufacture, including import, processing, distribution in commerce, commercial use and disposal of methylene chloride to prevent unreasonable risk of injury to health. Because the EPA determined the chemical presents an unreasonable health risk within the United States, the rule applies even if methylene chloride is manufactured, processed or distributed solely for export.

As noted, the EPA adopted a de minimis threshold of 0.1% to account for impurities and the unintended presence of methylene chloride; thus, the final rule applies only when methylene chloride is present in a formulation at 0.1% or greater. The final rule also applies only to chemical substances as defined under TSCA Section 3 and excludes from the definition chemical substance uses subject to the Federal Food, Drug and Cosmetic Act and the Federal Insecticide, Fungicide and Rodenticide Act.

Workplace Chemical Protection Program

The EPA is implementing the Workplace Chemical Protection Program (WCPP) for certain COUs, including among others, domestic manufacturing; import; processing as a reactant; processing for incorporation into a formulation, mixture or reaction product; processing in repackaging; processing in recycling; and industrial and commercial use as a laboratory chemical.

WCPP requirements take effect on May 5, 2025, for the private sector and on Nov. 9, 2026, for federal agencies and federal contractors acting for or on behalf of the federal government, at which point entities would be required to conduct initial monitoring.

Chemical Exposure Limits

The EPA requires each owner or operator ensure the airborne concentration of methylene chloride does not exceed the existing chemical exposure limit (ECEL) or EPA short-term exposure limit (STEL) for all potentially exposed persons no later than Aug. 1, 2025, for the private sector, or no later than Feb. 8, 2027, for federal agencies and federal contractors.

The EPA is codifying that owners or operators must ensure the airborne concentration of methylene chloride within the personal breathing zone of potentially exposed persons remains at or below 2 parts per million (ppm) as an eight-hour time-weighted average (TWA) ECEL, with an action level of 1 ppm as an eight-hour TWA.

The EPA is promulgating as proposed that owners or operators must also ensure the airborne concentration of methylene chloride within the personal breathing zone of potentially exposed persons remains at or below a 15-minute TWA, or EPA STEL, of 16 ppm. The EPA is adopting the ECEL and EPA STEL for certain occupational COUs to ensure no person is exposed to inhalation of methylene chloride in excess of these concentrations.

The final rule requires owners or operators determine each potentially exposed person’s exposure by taking a personal breathing zone air sample or by taking personal breathing zone air samples representative of each potentially exposed person’s exposure. The latter involves taking one or more samples for at least one potentially exposed person in each job classification in a work area during every work shift, and the person sampled is expected to have the highest methylene chloride exposure; or when one or more samples are taken that indicate the highest likely 15-minute exposures during such operations for at least one potentially exposed person in each job classification in the work area during every work shift, and the person sampled is expected to have the highest methylene chloride exposure.

Air sampling is required to measure ambient concentrations for methylene chloride without taking respiratory protections into account as sampling is being performed. The final rule also requires the owner or operator ensure, for initial and periodic monitoring, that their exposure monitoring methods are accurate to a confidence level of 95% and are within ±25% of airborne concentrations of methylene chloride above the eight-hour TWA ECEL or the 15-minute TWA EPA STEL, or within (plus or minus) 35% for airborne concentrations of methylene chloride at or above the ECEL action level but at or below the eight-hour TWA ECEL. To ensure compliance for monitoring activities, the EPA is adopting recordkeeping requirements and will require owners or operators document their choice of monitoring method.

Exposure Control Plan

The final rule requires entities implementing the WCPP use elimination and substitution, followed implementation of engineering controls, administrative controls and work practices prior to requiring the use of personal protective equipment (PPE) as a means of controlling inhalation exposures below the EPA’s ECEL or STEL. The EPA expects that, for COUs for which the EPA is requiring a WCPP, “compliance at most workplaces would be part of an established industrial hygiene program that aligns with the hierarchy of controls.”

Under the final rule, the owner or operator must demarcate any area where airborne concentrations of methylene chloride are reasonably expected to exceed the ECEL or the EPA STEL. The demarcation may be done “in any manner that adequately establishes and alerts potentially exposed persons to the boundaries of the area and minimizes the number of authorized persons exposed to methylene chloride within the regulated area.”

The final rule is a more defensible and flexible outcome than expected.

Personal Protective Equipment

Where elimination, substitution, engineering and administrative controls are not feasible or sufficiently protective to reduce the air concentration to or below the ECEL, or if inhalation exposure above the ECEL is still reasonably likely, EPA is codifying its minimum respiratory PPE requirements based on an owner or operator’s measured air concentration for one or more potentially exposed persons and the level of PPE needed to reduce exposure to or below the ECEL. The EPA is requiring that the owner or operator comply with the Occupational Safety and Health Administration’s (OSHA) General Requirements for PPE standard for application of a PPE program. The EPA also requires that the owner or operator comply with 29 C.F.R. Section 1910.134 for proper use, maintenance, fit-testing and training on respirator use.

The final rule also requires dermal protection, recordkeeping, notification and other requirements too numerous to summarize here to minimize and protect potentially exposed persons from dermal exposure, including 29 C.F.R. Section 1910.1052(h) and (i).

Prohibitions on Methylene Chloride

The final rule prohibits manufacture, processing, distribution and all industrial and commercial use of methylene chloride and methylene chloride-containing products, except for those uses that will continue under the WCPP. Surprisingly, the EPA codified timeframes longer than proposed for the prohibition of manufacture, processing, distribution and commercial use of methylene chloride broadly, and for particular uses such as commercial use of methylene chloride in adhesives and sealants in aircraft, space vehicles and turbine applications; and commercial use of methylene chloride in paint and coating removal for the refinishing of wooden pieces of artistic, cultural or historical value.

The final rules impose staggered prohibitions, beginning at the top of the supply chain. The timeframes for prohibitions following the publication of the final rule in the Federal Register will be:

Within 270 days of publication of the final rule in the Federal Register for prohibitions on distributing to retailers;
Within 360 days for prohibitions on distribution by retailers;
Within 360 days for prohibitions on manufacturing;
Within 450 days for prohibitions on processors;
Within 630 days for prohibitions on all distributors other than retailers; and
Within 720 days of publication in the Federal Register for prohibitions on most industrial and commercial use.

Prohibitions for Consumer Use of Methylene Chloride

The final rule prohibits the manufacture, processing and distribution in commerce of methylene chloride and methylene chloride-containing products for all consumer use. Retailers are prohibited from distributing methylene chloride and all methylene chloride-containing products to prevent products intended for industrial and commercial use under the WCPP from being purchased by consumers. The final rule includes a 10-year exemption for certain emergency uses in furtherance of the National Aeronautics and Space Administration’s mission.

Discussion

From the industry’s perspective, the final rule is a more defensible and flexible outcome than expected. The EPA used a risk-based evaluation to support its de minimis threshold for methylene chloride in formulations.

Some may question the agency’s decision to prohibit most industrial and commercial uses. Persons with these COUs may be capable of complying with EPA’s WCPP. The EPA appears, however, to be interpreting the “extent necessary” provision of TSCA Section 6(a) based on the ability of persons to demonstrate compliance with its risk management measures prior to the EPA issuing its final rule rather than prior to using methylene chloride in the workplace. This position seems amenable to legal challenge.

Despite the flexibility of the final rule, not all stakeholders will be supportive, and litigation seems inevitable. The EPA has, however, demonstrated that it will consider information provided during the comment period and will use it to inform its risk management decisions. Stakeholders are encouraged to review the final rule carefully and in forthcoming risk management rulemakings, provide data and information to the EPA as early as possible to avoid or minimize the possibility of future prohibitions under TSCA.