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###### Environmental Protection Agency

          - [EPA-HQ-OPPT-2018-0435]; FRL-8807-03-OCSPP]

# AGENCY:

Environmental Protection Agency (EPA).

      ( print page 639)    

# ACTION:

Notice.

# SUMMARY:

The Environmental Protection Agency (EPA or Agency) is announcing the availability of the final risk evaluation under the Toxic Substances Control Act (TSCA) for diisodecyl phthalate (DIDP). The purpose of risk evaluations under TSCA is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, without consideration of costs or non-risk factors, including unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, under the conditions of use. EPA used the best available science to prepare this final risk evaluation and determined, based on the weight of scientific evidence, that DIDP poses unreasonable risk to human health. Under TSCA, EPA must initiate risk management actions to address the unreasonable risk.

# ADDRESSES:

                        The docket for this action, identified by docket identification (ID) number EPA-HQ-OPPT-2018-0435, is available online at                         *https://www.regulations.gov.*                         Additional information about dockets generally, along with instructions for visiting the docket in-person, is available at                         *https://www.epa.gov/​dockets.*

# FOR FURTHER INFORMATION CONTACT:

*For technical information:*                         Brianne Raccor, Existing Chemical Risk Management Division (7404M), Office of Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460-0001; telephone number: (202) 564-0303; email address:                         *raccor.brianne@epa.gov.*

*For general information:*                         The TSCA-Hotline, ABVI-Goodwill, 422 South Clinton Ave., Rochester, NY 14620; telephone number: (202) 554-1404; email address:                         *TSCA-Hotline@epa.gov.*

# 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, processing, distribution, use, and disposal of DIDP, 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 technical contact listed under                     **FOR FURTHER INFORMATION CONTACT**                    .                

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

The Agency conducted 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 all chemical substance risk evaluations. Each risk evaluation must be conducted consistent with the best available science, be based on the weight of the scientific evidence, and consider reasonably available information. 15 U.S.C. 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 the final risk evaluation under TSCA for DIDP. The purpose of risk evaluations under TSCA is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, without consideration of costs or non-risk factors, including unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, under the conditions of use. EPA has used the best available science to prepare this final risk evaluation and based on the weight of scientific evidence, determined that DIDP poses unreasonable risk to human health. Upon a determination of unreasonable risk, EPA must initiate risk management action as required pursuant to TSCA section 6(a), 15 U.S.C 2605(a), to address the unreasonable risk.

## II. Background

### A. What is DIDP?

DIDP is a common chemical name for the category of chemical substances that includes the following substances: 1,2- benzenedicarboxylic acid, 1,2-diisodecyl ester (CASRN 26761-40-0) and 1,2-benzenedicarboxylic acid, di-C9-11-branched alkyl esters, C10-rich (CASRN 68515-49-1). Both CASRNs contain mainly C10 dialkyl phthalate esters. DIDP is manufactured (including imported), processed, distributed, and disposed as part of industrial, commercial, and consumer conditions of use. DIDP is used primarily as a plasticizer to make flexible polyvinyl chloride (PVC). It is also used to make building and construction materials; automotive articles; and other commercial and consumer products including adhesives and sealants, paints and coatings, and electrical and electronic products. The production volume of DIDP has increased significantly over the past decade from between 100 and 250 million pounds in 2015 to between 100 million and 1 billion pounds in 2019.

### B. Risk Evaluation of DIDP

In May 2019, EPA received a request to conduct a risk evaluation DIDP from ExxonMobil Chemical Company, Evonik Corporation, and Teknor Apex, through the American Chemistry Council's High Phthalates Panel (ACC HPP). In December 2019, EPA notified ACC HPP that the Agency had granted the manufacturer requested risk evaluation. See EPA-HQ-OPPT-2018-0435 (Ref. 1). In November 2020, EPA released the draft scope of the DIDP risk evaluation (Ref. 2) and, after considering public comments, issued the final problem formulation in August 2021 (Ref. 3). On February 29, 2024, EPA released a draft risk evaluation for public comment and peer review by the Science Advisory Committee on Chemicals (SACC). (Ref. 4). The draft documents and public comments are in docket ID number EPA-HQ-OPPT-2024-0073. A non-technical summary is also available (Ref. 5). Given the shared peer review and chemical similarities with DINP, a shared set of responses to peer review and public comments will be available in January 2025 when the final Diisononyl Phthalate (DINP) risk evaluation is released (Ref. 6).

## III. Unreasonable Risk Determination

                    EPA has determined that DIDP presents an unreasonable risk of injury to human health under the conditions of use. EPA did not identify risk of injury to the environment that would contribute to the unreasonable risk determination for DIDP. EPA has determined that the unreasonable risk to human health presented by DIDP is due to non-cancer effects (                    *i.e.,*                     reduced offspring survival) in female workers of reproductive age from acute inhalation exposures and acute aggregated exposures. The unreasonable risk determination is based on the information within the risk evaluation, the appendices, and technical support documents of the risk evaluation in accordance with TSCA section 6(b). It is also based on TSCA's best available science (TSCA section 26(h)), weight of scientific evidence standards (TSCA section 26(i)), and relevant implementing regulations in 40 CFR part 702, including, to the extent practicable, the amendments to the procedures for chemical risk evaluation                           ( print page 640)                        under TSCA finalized in May 2024 (89 FR 37028; May 3, 2024).                

Between release of the draft risk evaluation and finalization of the DIDP risk evaluation, EPA updated the risk determination to find that six COUs contribute to unreasonable risk of DIDP based on new information identified by EPA, information provided by public commenters, and recommendations of the SACC. These changes stem from consideration of 1) multiple factors impacting occupational exposure during spray application, 2) applicability of developmental effects to average adult workers, and 3) identification of DIDP-containing products that could be spray applied. The COUs that EPA identified as presenting unreasonable risk were for acute exposure scenarios in which unprotected female workers of reproductive age were to spray adhesives and sealants; paints and coatings; lacquers, stains, varnishes, and floor finishes; or penetrants and inspection fluids that contain DIDP, because doing so could create high concentrations of DIDP in mist that an unprotected worker could inhale. The human health hazard that EPA identified as having the strongest evidence to support this risk evaluation is developmental toxicity, which means that laboratory animals dosed with DIDP had litters where more rodent offspring died than was the case with the litters of rodents that were not dosed with DIDP. As the most sensitive health effects of concern relate to exposure of the developing fetus during gestation, the population to which this risk determination is most relevant is female workers of reproductive age.

                    Consistent with the statutory requirements of TSCA section 6(a), EPA will propose a risk management regulatory action to the extent necessary so that DIDP no longer presents an unreasonable risk. EPA expects to focus its risk management action on the conditions of use that significantly contribute to the unreasonable risk. However, it should be noted that, under TSCA section 6(a), EPA is not limited to regulating the specific activities found to drive unreasonable risk and may select from among a suite of risk management requirements in section 6(a) related to manufacture (including import), processing, distribution in commerce, commercial use, and disposal as part of its regulatory options to address the unreasonable risk. As a general example, EPA may regulate upstream activities (                    *e.g.,*                     processing, distribution in commerce) to address downstream activities (                    *e.g.,*                     industrial and commercial uses) driving unreasonable risk, even if the upstream activities do not drive the unreasonable risk. Like the prioritization and risk evaluation processes, there is an opportunity for public comment on any proposed risk management actions.                

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

## IV. References

                    The following is a listing of the documents that are specifically referenced in this document. The docket includes these documents and other information considered by EPA, including documents that are referenced within the documents that are included in the docket, even if the referenced document is not physically located in the docket. For assistance in locating these other documents, please consult the person listed under                     **FOR FURTHER INFORMATION CONTACT**                    .                

                        1. EPA. Di-isodecyl Phthalate (DIDP); Manufacturer Request for Risk Evaluation Under the Toxic Substances Control Act (TSCA); Notice of Availability and Request for Comments.                         **Federal Register**                        . 84 FR 42914, August 19, 2019 (FRL-9998-26).                    

                        2. EPA. Di-isodecyl Phthalate (DIDP); Draft Scope of the Risk Evaluation to be Conducted Under the Toxic Substances Control Act (TSCA); Notice of Availability and Request for Comments.                         **Federal Register**                        . 85 FR 76077, November 27, 2020 (FRL-10017-14).                    

                        3. EPA. Di-isodecyl Phthalate (DIDP); Final Scope of the Risk Evaluation To Be Conducted Under the Toxic Substances Control Act (TSCA); Notice of Availability.                         **Federal Register**                        . 86 FR 48695, August 31, 2021 (FRL-8807-01-OCSPP).                    

                        4. EPA. Di-isodecyl Phthalate (DIDP) and Di-isononyl Phthalate (DINP); Science Advisory Committee on Chemicals (SACC) Peer Review of Draft Documents; Notice of SACC Meeting; Availability; and Request for Comment.                         **Federal Register**                        . 89 FR 43847, May 20, 2024 (FRL-11760-02-OCSPP).                    

5. EPA. Nontechnical Summary of the TSCA Risk Evaluation for Diisodecyl Phthalate (DIDP). December 2024. (EPA Document ID No. EPA-740-S-24-008).

6. EPA. Comment Summary and Responses for Diisodecyl Phthalate (DIDP) and Diisononyl Phthalate (DINP). December 2024.

*Authority:*15 U.S.C. 2601*et seq.*

Dated: December 20, 2024.

Michal Freedhoff,

Assistant Administrator, Office of Chemical Safety and Pollution Prevention.

[FR Doc. 2024-31280 Filed 1-3-25; 8:45 am]

BILLING CODE 6560-50-P