August 6, 2026 | Contact EPA's Press Office (press@epa.gov)

Draft TSCA Risk Evaluations for Two Chemicals

WASHINGTON - The U.S. Environmental Protection Agency (EPA) is advancing its review of o-dichlorobenzene (oDCB) and p-dichlorobenzene (pDCB) under the Toxic Substances Control Act (TSCA) by releasing draft risk evaluations for public comment. Both chemicals are found in products used in homes and workplaces and can evaporate into the air. For pDCB, which is used in some air care and deodorizing products, indoor air can be a key exposure route for people who use those products. Evaluating each chemical across its conditions of use and exposure pathways is how EPA determines where new protections may be needed and where existing safeguards are sufficient.

EPA applied systematic review and weighed the reasonably available, peer-reviewed science alongside information submitted to the Agency. The complete draft evaluations, technical support documents, and underlying data will be available in the public dockets and on EPA's website. The draft evaluations preliminarily found:

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


• pDCB (p-dichlorobenzene) contributes to unreasonable risk to workers from 7 conditions of use through inhalation and dermal exposure, and to consumers via inhalation from air care products. Non-cancer hazards evaluated include developmental, liver, and respiratory toxicity.


• For both chemicals, the draft risk evaluations found no unreasonable risk to the general population through ambient outdoor air, including fenceline communities, or to the environment. This is separate from the consumer-use exposures above, where the drafts do identify some conditions of use as contributing to unreasonable risk.

Consistent with TSCA, EPA considered potentially exposed or susceptible subpopulations, including workers and groups that may be more susceptible, in characterizing risk. EPA's draft worker risk estimates do not assume the use of personal protective equipment (PPE) as the basis for the risk determination; the drafts separately discuss how PPE and other controls could reduce exposure. EPA welcomes comments and data on the occupational and consumer exposure scenarios, on potentially exposed or susceptible subpopulations, and on additional health endpoints.

For pDCB, EPA's draft determination is that it is not likely to be carcinogenic to humans, based on a non-mutagenic, threshold-dependent mode of action for the liver tumors observed in animals. EPA recognizes that IARC and the National Toxicology Program have classified pDCB differently and specifically invites comments and data on this evaluation.

These are draft findings, and EPA wants feedback. The 60-day comment period is how EPA hears from independent experts, workers, communities, and the public before finalizing the risk evaluations. All current protections and product label directions remain in place while EPA completes these reviews; releasing draft evaluations does not alter any existing safeguard. If EPA continues to find unreasonable risk, it will propose risk-management actions under TSCA section 6(a) to address those exposures. EPA is working toward the February 12, 2027, consent-decree deadline for the final evaluations.

Upon publication of the Federal Register notice, EPA will accept comments for 60 days at regulations.gov: oDCB via EPA-HQ-OPPT-2018-0444 and pDCB via EPA-HQ-OPPT-2018-0446.

— End of Press Release —

Comments by the KnowYourH2O Team

Plain Language: What Are These Chemicals?

What is o-Dichlorobenzene (oDCB)? o-Dichlorobenzene (CASRN 95-50-1) is a colorless liquid with a mild aromatic odor. It is primarily used in manufacturing dyes, paints, and pigments, and in cleaning, degreasing, and painting products. Workers who handle it regularly and consumers who use products containing it may be exposed through inhalation or skin contact.

What is p-Dichlorobenzene (pDCB)? p-Dichlorobenzene (CASRN 106-46-7) is a colorless to white solid with a strong, sharp odor — the same chemical found in many mothballs and solid air fresheners. It is used in plastics manufacturing, chemical production, and as an odor-masking agent in various consumer products. Indoor air exposure is a primary concern for people who use these products at home.

Recommended Action

1. If you are a professional with knowledge of these compounds, please comment on the proposed regulations.
   
   
2. If you are a water customer, you may want to get your water tested. If you want to screen your City Water or Tap Water or your Well Water for these chemicals and others, please follow the highlighted link to the appropriate informational water test.
   
   
3. For individuals that use private wells or live near their source waters, you may want to order a Neighborhood Hazard Report to see if the associated activities are near your home and water source.
   
   
4. Want to understand your drinking water better? Order our Drinking Water Guide for Well Water and City Water — a plain-language booklet covering what's in your water, what it means for your health, and what you can do about it.