SUPPLEMENTARY INFORMATION:

I. Executive Summary

A. Does this action apply to me?

This action is directed to the public in general and may be of particular interest to those involved in the manufacture (defined under TSCA section 3(9) to include import), processing, distribution, use, and disposal of o -dichlorobenzene and p -dichlorobenzene, related industry trade organizations, non-governmental organizations with an interest in human and environmental health, State and local governments, Tribal Nations, and/or those interested in the assessment of risks involving chemical substances and mixtures regulated under TSCA. As such, the Agency has not attempted to describe all the specific entities that this action might apply to. If you need help determining applicability, consult the relevant technical contact listed under FOR FURTHER INFORMATION CONTACT . ( printed page 51489)

B. What is the Agency's authority for taking this action?

The Agency is conducting this risk evaluation under TSCA section 6, 15 U.S.C. 2605, which requires that EPA conduct risk evaluations on chemical substances and identifies the minimum components EPA must include in the risk evaluations. Each risk evaluation must be conducted consistent with the best available science, be based on the weight of the scientific evidence, consider reasonably available information, and not consider costs or non-risk factors (15 U.S.C. 2605(b)(4), 2625(h), (i), and (k)). See also the implementing procedural regulations at 40 CFR part 702.

C. What action is the Agency taking?

EPA is announcing the availability of and seeking public comment on draft risk evaluations under TSCA for o -dichlorobenzene and p -dichlorobenzene, including related technical support documents. EPA used the best available science to prepare these draft risk evaluations and preliminarily determined, based on the weight of scientific evidence, that o -dichlorobenzene and p -dichlorobenzene present unreasonable risk to human health driven primarily by certain COUs analyzed in the draft risk evaluations.

D. What should I consider as I prepare my comments?

1. Submitting CBI

Do not submit CBI to EPA through www.regulations.gov or email. If you wish to include CBI in your comment, please follow the applicable instructions at www.epa.gov/​dockets/​commenting-epa-dockets#rules and clearly mark the information that you claim to be CBI. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR parts 2 and 703, as applicable.

2. Tips for preparing your comments.

When preparing and submitting your comments, see the commenting tips at www.epa.gov/​dockets/​commenting-epa-dockets.

II. Background

A. What is o-Dichlorobenzene?

o -Dichlorobenzene is a clear to pale yellow liquid with a pleasant, aromatic odor. It exists in a liquid phase at ambient temperatures. o -Dichlorobenzene is processed as a reactant and incorporated into formulation, mixture, or reaction products. Industrial and commercial uses range from use as a solvent in dyes and pigments to use in lubricant and degreaser products and in inks and paint strippers. Consumer uses include lubricant and degreaser products, air care products, and other uses such as ceramics glazing and cleaning products. It has low to moderate solubility in aqueous systems and is a moderately volatile organic compound. Exposure to o- dichlorobenzene can occur via inhalation of vapors during use and via the dermal route through contact with solids or accidental splashing from liquid products. When released to water or soil, o -dichlorobenzene volatilizes to the surrounding atmosphere. Air is expected to be the primary pathway of exposure to o -dichlorobenzene in the environment.

B. What is p-Dichlorobenzene?

p -Dichlorobenzene is a colorless to white crystalline solid that has a strong, pungent odor and which is poorly soluble in water but miscible in most organic solvents. At ambient temperature, it undergoes sublimation, passing directly from a solid to a vapor state. Industrial and commercial uses of p- dichlorobenzene range from the manufacture of thermoplastic and use in solvents (which become part of product formulation or mixtures) to use in air care products as continuous-action air fresheners. Consumer uses include in air care products, lubricants and greases, and building and construction products. The volatilization of p- dichlorobenzene from these products has been identified as a potential mechanism of exposure. Thus, exposure to p- dichlorobenzene can occur via inhalation of vapors during use and via the dermal route through contact with solids or accidental splashing from liquid products. When released to water or soil, p -dichlorobenzene volatilizes to the surrounding atmosphere. Air is expected to be the primary pathway of exposure to p -dichlorobenzene in the environment.

C. Summary of Activities for the Risk Evaluations of o-and p-Dichlorobenzene

In December 2019, EPA announced its designation of o -dichlorobenzene (Docket ID: EPA-HQ-OPPT-2018-0444) and p -dichlorobenzene (Docket ID: EPA-HQ-OPPT-2018-0446) as high priority substances for risk evaluation under TSCA (84 FR 71924, December 30, 2019) (FRL-10003-15). In April 2020, EPA published and sought public comment on the draft scopes of the o -dichlorobenzene and p-dichlorobenzene risk evaluations (85 FR 19941, April 9, 2020) (FRL-10007-11-OCSPP), and, after considering public comments, issued the final scopes in September 2020 (85 FR 55281, September 4, 2020) (FRL-10013-90-OCSPP). In April 2026, EPA released the draft hazard assessments for both o -dichlorobenzene and p -dichlorobenzene for public comment and external peer review by the Science Advisory Committee on Chemicals (SACC) (91 FR 19131, April 14, 2026) (FRL-13266-01-OCSPP). As part of the SACC deliberations, the Agency held a virtual public meeting to discuss the draft hazard assessments for both o -dichlorobenzene and p -dichlorobenzene in June 2026. For more information about this meeting, go to the SACC website at www.epa.gov/​tsca-peer-review/​science-advisory-committee-chemicals-meetings. These documents, other supporting documents, and public comments are in docket ID number EPA-HQ-OPPT-2026-1189 at www.regulations.gov. The draft risk evaluations for o -dichlorobenzene and p -dichlorobenzene are being released with this notice and are available at www.regulations.gov in Docket ID numbers EPA-HQ-OPPT-2018-0444 and EPA-HQ-OPPT-2018-0446, respectively.

EPA is now opening a 60-day public comment period on the draft risk evaluations for both o -dichlorobenzene and p -dichlorobenzene. External peer review is not needed on the draft risk evaluations and chemistry, fate, release, and exposure assessments because in addition to the peer review of the draft hazard assessments, as noted above, the methodologies used in the development of the draft risk evaluations have been previously peer reviewed by the SACC in published risk evaluations for 1,1-dichloroethane (90 FR 26581, June 23, 2025) (FRL-11809-04), 1,3-butadiene (91 FR 264, January 5, 2026) (FRL-12241-05-OCSPP), and phthalates (91 FR 373, January 6, 2026) (FRL-13111-01-OCSPP), as well as the Draft TSCA Screening Level Approach for Assessing Ambient Air and Water Exposures to Fenceline Communities (87 FR 3294, January 21, 2022) (FRL-9392-01-OCSPP).

III. Request for Comment

EPA seeks feedback on the assessment of risk presented in the draft risk evaluations for o -dichlorobenzene and p -dichlorobenzene, copies of which are available in their respective dockets, and encourages all potentially interested parties, including individuals, governmental and non-governmental organizations, non-profit organizations, academic institutions, research institutions, and private sector entities to comment on the draft risk evaluation. To the extent possible, the Agency asks commenters to please cite any public ( printed page 51490) data related to or that support comments provided, and to the extent permissible, describe any supporting data that is not publicly available.

EPA 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 o- dichlorobenzene and p -dichlorobenzene; exposure controls and personal protective equipment used to mitigate o- dichlorobenzene and p -dichlorobenzene exposures in industrial settings; time-weighted average occupational inhalation exposures using monitoring information from multiple shift lengths; characterization of risks associated with the manufacture, use, and disposal of o- dichlorobenzene and p -dichlorobenzene; and determination of unreasonable risks associated with these substances.

Although EPA seeks public comment on all aspects of the draft risk evaluation packages, the Agency particularly seeks comments on the following for o- dichlorobenzene:

• Process descriptions, worker activities, concentrations (in air, product, or process) and current prevalence of the followingo -dichlorobenzene 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 U.S. 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 containingo -dichlorobenzene including product availability, ingredients and composition, and use instructions.
• Whether and how exposure controls and personal protective equipment (PPE) are used during the manufacture, processing, and use ofo -dichlorobenzene for each of the COUs depicted in Table ES-1 of the Draft Risk Evaluation for o- Dichlorobenzene. Although EPA 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 (i.e., mapping) of the Industrial Use of Solvents 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, 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-min exposure values, including extrapolation of the hour occupational exposure value to a 15-min time-weighted average and extrapolation of the original animal data down to a 30-min duration to calculate a short-term exposure value based on principles of (ten Bergeet al., 1986).
• The modeling approach used to determine inhalation exposure too -dichlorobenzene 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. For example, EPA 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.

The Agency particularly seeks comments on the following for p- dichlorobenzene:

• Process descriptions, worker activities, concentrations, and current prevalence of COUs ofp -dichlorobenzene, including typical schedules (shifts per year and hours per shift) for workers at sites using p- dichlorobenzene.
• 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 ofp -dichlorobenzene ( 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, liquidp- dichlorobenzene is present.
• Reasonableness of the assumptions used to estimate dermal exposure, including for occupational non-users (ONUs).
• 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 top -dichlorobenzene, which is a solid at room temperature and also sublimates.
• Use ofp -dichlorobenzene in abrasive grinding wheels, in particular with respect to exposure for both workers and ONUs.
• Prevalence of the use ofp -dichlorobenzene in laboratories.
• Whether and how exposure controls and PPE are used during the manufacture, processing, and use ofp -dichlorobenzene for each of the COUs, especially the use of gloves ( e.g., prevalence of use and glove material) during commercial use of p -dichlorobenzene in air care products, and

1. Although EPA has test order data, additional information on when and where exposure controls and PPE are used would be informative.

• Whether it is appropriate to normalize a 1-hour time weighted average (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.

IV. Next Steps

EPA will consider comments received on the draft risk evaluations as well as input from the SACC peer review of the draft hazard assessments and then announce the availability of the final risk evaluations for o -dichlorobenzene and p -dichlorobenzene. Under TSCA section 6, EPA must use the final risk evaluation as a basis to determine, based on the weight of scientific evidence, whether or not a chemical presents an unreasonable risk to health or the environment, without consideration of costs or other non-risk factors, including unreasonable risks to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, under the chemical's COUs.

If EPA determines in its final risk evaluation that a chemical presents an unreasonable risk to health or the environment, the chemical will move to risk management action under TSCA section 6(a) for the relevant COUs. Like the prioritization and risk evaluation processes, there will be an opportunity ( printed page 51491) for public comment on any proposed risk management actions.

For more information about the TSCA risk evaluation process for existing chemicals, go to www.epa.gov/​assessing-and-managing-chemicals-under-tsca.

(Authority: 15 U.S.C. 2601 et seq.)

91 FR 51488