As one of the more robust and recently modernized statutes controlling industrial chemicals in the US, the Toxic Substances Control Act (TSCA) is systematically used to advance the US Environmental Protection Agency’s (EPA) regulatory agenda. In past articles, we reported on TSCA activities worth watching, with two of them concerning risk management decisions regarding trichloroethylene (TCE) and perchloroethylene (PCE), which is also known as tetrachloroethylene. On December 9 and 11, 2024, EPA announced sweeping restrictions on consumer, commercial, and industrial uses of TCE and PCE, as well as another chemical, carbon tetrachloride (CTC), with the final rules effective in early 2025. This article delves into key aspects of risk management rules, examining the similarities and differences of the regulatory contexts for each substance.
What is Trichloroethylene (TCE) & What are EPA’s New Requirements?
TCE (CAS 79-01-6) is a volatile organic compound used in industrial and commercial processes. It can also be found in consumer goods such as cleaning and furniture care products, automotive care products, and arts and crafts materials. This industrial chemical was among the ten substances prioritized for assessment under the Reformed (2016) TSCA paradigm. Currently, most of the TCE on the market is used as a feedstock for refrigerant production. Smaller amounts are used as a degreasing solvent. Because of its past uses, TCE may be found at certain contaminated sites, most commonly in groundwater near dry-cleaning shops, former industrial degreasing operations, and locations of improperly disposed industrial waste.
Prohibition of Industrial, Commercial, and Consumer Uses of Trichloroethylene (TCE)
On January 9, 2023, EPA announced a final determination declaring that TCE poses an unreasonable risk of injury to human health in almost all applications. The EPA’s finding that TCE poses unreasonable risks to the health of workers, non-users in close proximity to TCE, consumers, and bystanders followed a November 2020 risk evaluation, public comments, peer review, and recent policy changes. The uses singled out in the determination were:
- Manufacturing (including import)
- Processing as a reactant/intermediate and into a formulation and articles
- Repackaging and recycling
- Industrial and commercial use as a solvent in adhesives, sealants, lubricants, greases, functional fluids, paints, coating, and a variety of cleaning products
- Commercial and consumer use in several products
- Disposal
On December 9, 2024, EPA announced a risk management decision to act on the unreasonable risk conclusion by implementing mandatory prohibitions and phaseouts within certain compliance timeframes for several conditions of use, which are detailed below.
In addition to the prohibitions and phaseouts, EPA has also set the industrial worker exposure inhalation limit for airborne TCE—also known as the Interim Existing Chemical Exposure Limit (ECEL)—to 0.2 parts per million (ppm) (1.07 milligrams [mg]/cubic meter [m3]) calculated as an 8-hour time-weighted average (TWA). This also applies to wastewater operators and remediation professions where workers are potentially exposed to contaminated groundwater.
The new limit is 500 times lower than the current Occupational Safety and Health Administration (OSHA) standard of 100 ppm and 5,000 times lower than EPA’s TSCA Action Level TWA of 0.1 ppm.
The wastewater-equivalent ECEL screening level cited by EPA is 0.00282 milligrams per liter (mg/L)—lower than the enforceable Maximum Contaminant Level of 0.005 mg/L for TCE. Under the new restrictions, facilities generating solid waste with TCE above the Resource Conservation and Recovery Act (RCRA) regulatory level of 0.5 mg/L based on the Toxicity Characteristic Leaching Procedure will need to comply with RCRA requirements without the possibility of using dilution as a treatment method.
As an additional requirement, air and wastewater ECELs, air/dermal exposure controls and personal protective equipment (PPE), hazard training, and workplace TCE monitoring requirements must be included in the Workplace Chemical Protection Plan (WCPP).
The TCE risk management rule also comes with record-keeping and downstream notification requirements for affected workers and value chain members (so do the PCE and CTC rules discussed below). However, one major accommodation is the availability of 0.1 percent by weight threshold for TCE in products, which aligns with OSHA’s Hazard Communication Standard for disclosing carcinogens in Safety Data Sheets. Moreover, under defined scenarios, TCE may be claimed as a byproduct and not subject to the rule, like exemptions granted under TSCA Chemical Data Reporting.
Owners and operators of cleanup sites are responsible for ensuring that potentially exposed persons handling TCE-impacted wastewater are protected against ECEL exceedances and dermal contact. However, a groundwater remediation system would have to be classified as a commercial disposal method to either industrial pre-treatment/treatment or Publicly Owned Treatment Works (POTW), subject to a National Pollutant Discharge Elimination System permit to fall under this rule.
Scientific Basis – Immune System Effects via Inhalation and Transdermal Uptake of Trichloroethylene (TCE)
While multiple adverse effects were cited in the rule, such as developmental toxicity, reproductive toxicity, liver toxicity, kidney toxicity, neurotoxicity, and cancer, key points supporting EPA’s determination were associated with immune system effects after acute and chronic inhalation as well as dermal exposure. EPA’s new TCE announcement supersedes the 2020 TCE regulatory determination and affirms the new policy of not considering OSHA’s required use of PPE in risk evaluation.
What is Perchloroethylene (PCE) & What are EPA’s New Requirements?
Many of the general TCE TSCA compliance requirements discussed above also apply to PCE, with specific differences noted below.
PCE is a volatile organic liquid that has many uses as an industrial solvent, degreaser in dry cleaning/ parts washing, feedstock in the manufacturing of fluorinated compounds, and a petrochemical catalyst regenerator in isomerization and reforming processes.
EPA completed a final risk evaluation of PCE in December 2022, which resulted in a draft risk management rule published on June 16, 2023, subject to public comment on the unreasonable risk determination. EPA considered comments before announcing the final rule on December 9, 2024.
EPA’s decision was based on all conditions of use and the associated risks of neurotoxicity (vision and cognitive effects) from chronic inhalation and dermal exposure. PCE is also stated to have adverse impacts on the kidneys, the liver, the immune system, reproduction, and development. EPA considers PCE a carcinogen. To control the unreasonable risks associated with PCE exposure, EPA has taken the following risk management measures.
Prohibitions and Requirements for Industrial, Commercial, and Consumer Uses of Tetrachloroethylene (PCE)
Like TCE, EPA developed an inhalation ECEL and AL at 0.14 ppm (0.98 mg/m3) and 0.10 ppm, respectively, which are also much lower than the current OSHA exposure limit of 100 ppm.
However, recycling and disposal activities are exempt from ECEL and the related implementation measures since EPA deemed that these scenarios do not contribute to unreasonable risk. Moreover, the PCE rule does not establish wastewater-based ECELs.
Nevertheless, the TSCA occupational limit may very well apply to many workers, including those dealing with environmental remediation. For refineries that rely on PCE as a catalyst regenerator, the final rule recognizes the criticality of this substance to ensure a steady fuel supply in the US. As such, it is not banned for that use as long as refineries ensure sufficient worker protection as prescribed in the rule and WCPPs.
The prohibitions and requirements for industrial, commercial, and consumer uses of PCE are detailed below:
What is Carbon Tetrachloride (CTC) & What are EPA’s New Requirements?
The third substance subject to recent final risk management rulemaking is carbon tetrachloride (CTC). It was once used as a degreaser, fire suppressant, and pesticide, though all consumer applications have since been banned. The recent announcement concerns the remaining uses, which consist of refrigerant production, aerosol propellants, and foam-blowing agents.
Like TCE and PCE, the final risk management rule imposes WCPPs, worker inhalation limits, monitoring, employee notifications, training, dermal contact and other workplace controls/PPE for permitted uses, including domestic manufacturing, import, production and processing of hydrofluorocarbons and other industrial agents, as well as disposal. Previously discussed recordkeeping, value chain notifications, and byproduct exemptions also apply to CTC except for the threshold quantity, which is defined for CTC as the presence of incidental “trace quantities.” EPA’s new restrictions on CTC are detailed below:
Risk management of CTC commenced with risk evaluation in November 2020 and a revised risk determination in December 2022. The proposed risk management rule was published on July 28, 2023, and after a public comment period and revisions, the final version was announced on December 11, 2024.
EPA cited the need to protect workers against liver and adrenal cancer associated with chronic inhalation and dermal exposure—as well as liver toxicity due to acute dermal exposure—as the basis for the CTC conditions of use restrictions. Like TCE and PCE, EPA establishes an inhalation ECEL of 0.03 ppm (0.2 mg/m3) to protect against liver and adrenal cancers in workers, with an AL of 0.02 ppm. Prohibitions and WCPP requirements are to take effect as early as mid-2025, and 2026 for certain US Department of Defense applications.
What’s Worth Noting – “Whole Chemical Substance” Approach
Unlike previous risk evaluations, EPA’s change in PPE policy resulted in the so-called “whole chemical substance (WCS)” risk determination. This breaks from EPA’s former approach, which, based on use-specific conditions, took into consideration OSHA’s required respiratory, dermal, and other relevant exposure control measures. The agency acknowledged the enhanced conservatism in the WCS approach and incorporated these de facto exposure controls into the current risk management phase. This new approach explains divergences from OSHA’s occupational limits and low ECELs for TCE, PCE, and CTC.
How These Actions Impact Remediation Sites
Owners and operators of cleanup sites where workers are potentially exposed to TCE, PCE, and CTC in water (including contaminated wastewater, surface water, and groundwater) that is handled ex situ via methods such as “pump and treat” for the purpose of remediation, industrial treatment, pre-treatment, or discharge to POTWs are subject to risk management rule WCPP provisions. The applicable worker tasks include system operation and maintenance, as well as any sampling of the incoming or treated water. The rules do not consider worker activities at sites subject to “nature and extent” of groundwater assessments.
EPA’s Next Steps – Education, Guidance, and Implementation
The final rules will take effect 30 days after their publication in the Federal Register. On January 15, 2025, EPA will hold a public informational webinar on the PCE risk management rule. A similar webinar was already held for TCE on November 14, 2023. Materials from this webinar are available on EPA’s TCE page. CTC supporting documentation is also available on a dedicated page.