EPA Releases Draft TSCA Risk Evaluations for oDCB and pDCB, “Two Chemicals Found in Household and Commercial Products”

On August 10, 2026, the U.S. Environmental Protection Agency (EPA) announced the availability of and requested public comment on the draft risk evaluations under the Toxic Substances Control Act (TSCA) for o-dichlorobenzene (oDCB) and p-dichlorobenzene (pDCB). 91 Fed. Reg. 51488. EPA notes that the purpose of TSCA risk evaluations is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment under the conditions of use (COU), including unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, and without consideration of costs or non-risk factors. EPA is seeking public comment on the draft risk evaluations for oDCB and pDCB. Comments are due October 9, 2026.

In its August 6, 2026, press release, EPA states that the draft evaluations found that:

• oDCB contributes to unreasonable risk to workers from 14 COUs (inhalation, with dermal exposure from seven) and to consumers from one COU through inhalation. Non-cancer hazards evaluated include developmental, liver, and respiratory toxicity.

• pDCB contributes to unreasonable risk to workers from seven COUs through inhalation and dermal exposure, and to consumers via inhalation from air care products. Non-cancer hazards evaluated include developmental, liver, and respiratory toxicity.

EPA states that for both chemicals, the draft preliminary risk evaluations found no unreasonable risk to the general population through ambient outdoor air, including fenceline communities, or to the environment. EPA notes that this is separate from the consumer-use exposures above, where the drafts do identify some COUs as contributing to unreasonable risk.

Request for Comment

EPA states that it welcomes specific input on each section of the draft exposure assessments, draft hazard assessments, and draft risk evaluations with particular interest in the assessment of human exposures resulting from industrial, commercial, and consumer use of oDCB and pDCB; exposure controls and personal protective equipment (PPE) used to mitigate oDCB and pDCB exposures in industrial settings; time-weighted average (TWA) occupational inhalation exposures using monitoring information from multiple shift lengths; characterization of risks associated with the manufacture, use, and disposal of oDCB and pDCB; and determination of unreasonable risks associated with these substances. EPA particularly seeks comments on the following for oDCB:

• Process descriptions, worker activities, concentrations (in air, product, or process), and current prevalence of the following oDCB activities:
  
  
  1. Domestic manufacture;
     
     
  2. Processing as a reactant;
     
     
  3. Use in ink, toner, and colorant products;
     
     
  4. Use as a cleaning product in the dry cleaning or furnishing care industry, including evidence of use in the United States as a spot cleaner or alternative applications; and
     
     
  5. Consumer and commercial/occupational use as a cleaner for septic and cesspool tanks.
     
• Consumer use septic tank cleaner products containing oDCB, including product availability, ingredients and composition, and use instructions.
  
  
• Whether and how exposure controls and PPE are used during the manufacture, processing, and use of oDCB for each of the COUs depicted in Table ES-1 of the draft risk evaluation for oDCB. EPA states that although it has test order data, “additional information on when and where exposure controls and PPE are used (including for protection against inhalation and dermal exposures) would be informative.”
  
  
• The application of the Industrial Use of Solvents Occupational Exposure Scenario (OES) to the three COUs:
  
  
  1. Processing — Recycling;
     
     
  2. Industrial Use — Solvents (which become part of product formulation or mixture) — Printing ink manufacturing, paint and coating manufacturing, and synthetic dye and pigment manufacturing; and
     
     
  3. Industrial Use — Non-incorporative activities — Processing aids, not otherwise listed.
     
• The approach for derivation and utility of 15-minute exposure values, including extrapolation of the hour occupational exposure value to a 15-minute TWA and extrapolation of the original animal data down to a 30-minute duration to calculate a short-term exposure value based on a model developed from compiled acute inhalation toxicity data for volatile industrial chemicals (ten Berge et al., 1986).
  
  
• The modeling approach used to determine inhalation exposure to oDCB from the use of paints and coatings OES, based on the Automotive Refinishing Spray Coating Mist Inhalation Model, which estimates worker inhalation exposure based on the concentration of the chemical of interest in the nonvolatile portion of the sprayed product and the concentration of over sprayed mist/particles (OECD, 2011).
  
  
• The confidence ratings applied to hazard and exposure values in this risk evaluation. EPA states that, for example, it applied a Robust confidence rating for both hazard values, including for the liver point of departure when extrapolated to dermal exposure based on oral and inhalation data.
  

EPA states that it particularly seeks comments on the following for pDCB:

• Process descriptions, worker activities, concentrations, and current prevalence of COUs of pDCB, including typical schedules (shifts per year and hours per shift) for workers at sites using pDCB.

• The representativeness of monitoring data compared to the distribution of other sites at which the same OESs occur.

• Reasonableness of the assumption of negligible exposures from products with very low, residual concentrations of pDCB (i.e., Use of Lubricants and Greases and Use of Fuels and Related Products OESs).

• Whether dermal exposure to workers is foreseeable in any cases where a heated stream of neat, liquid pDCB is present.

• Reasonableness of the assumptions used to estimate dermal exposure, including for occupational non-users (ONU).

• Representativeness of high-end exposure estimates for intermediate dermal occupational exposures.

• Applicability of the Generic Model for Central Tendency and High-End Inhalation Exposure to Total and Respirable Particulates Not Otherwise Regulated to pDCB, which is a solid at room temperature and also sublimates.

• Use of pDCB in abrasive grinding wheels, in particular with respect to exposure for both workers and ONUs.

• Prevalence of the use of pDCB in laboratories.

• Whether and how exposure controls and PPE are used during the manufacture, processing, and use of pDCB for each of the COUs, especially the use of gloves (e.g., prevalence of use and glove material) during commercial use of pDCB in air care products.

• Whether it is appropriate to normalize a one-hour TWA concentration to a 24-hour TWA for a commercial exposure scenario, when the hazard value is based on a 24-hour exposure.

• The use of Indoor Environmental Concentrations in Buildings with Conditioned and Unconditioned Zones (IECCU) to model exposure to continuous action air fresheners for consumer and commercial COUs, including model assumptions.

Commentary

As expected, EPA continues to press ahead with its efforts required under the 2024 consent decree that resolved litigation over EPA’s lack of timeliness in completing 20 high-priority TSCA risk evaluations. As we have discussed in previous commentary, EPA continues to face substantial administrative challenges in completing and publishing various additional draft and final risk evaluations between now and the ultimate February 2027 deadline in the consent decree. EPA has been requesting Science Advisory Committee on Chemicals (SACC) review of parts of its risk assessments (usually the hazard assessment) and limiting its SACC review to those hazard reviews. Generally, as is the case again here, EPA is not requesting the SACC review full draft risk evaluations, largely because of time constraints. Time will tell how a court might view EPA’s peer review approach and if the court agrees that the approach meets the scientific standards in TSCA Section 26.