Risk Evaluation for Diisononyl phthalate (1,2-Benzene- dicarboxylic acid, 1,2- diisononyl ester) (DINP)

In January 2025, EPA released the final risk evaluation under the Toxic Substances Control Act (TSCA) for diisononyl phthalate (1,2-benzenedicarboxylic acid, 1,2-isononyl ester) (DINP).

EPA granted the manufacturer request for risk evaluation for DINP in December 2019.

Learn more about manufacturer-requested risk evaluations.

Find other information about other chemicals undergoing risk evaluations under TSCA.

On this page:

Risk Evaluation Findings
Background on DINP
Uses of DINP
Recent Activities and Opportunities for Public Comment
Supporting Documents

Risk Evaluation Findings

EPA has determined that DINP presents and unreasonable risk of injury to human health. DINP can cause developmental toxicity and harm the liver and can cause cancer at higher rates of exposure. Also, DINP can harm the developing male reproductive system, known as “phthalate syndrome” (e.g., decreased fetal testicular testosterone, male reproductive tract malformations, male nipple retention, and decreased male fertility). Therefore, EPA is including DINP in its cumulative risk analysis for six phthalates that demonstrate effects consistent with phthalate syndrome.

Workers may be exposed to DINP when making products or otherwise using DINP in the workplace. When it is manufactured or used to make products, DINP can be released into the water where most will end up in the sediment at the bottom of lakes and rivers. If released into the air, DINP will attach to dust particles and be deposited on land or into water. Indoors, DINP has the potential over time to come out of products and adhere to dust particles. If it does, people could inhale or ingest dust that contains DINP.

In the risk evaluation, EPA has determined that DINP poses unreasonable risk of injury to human health when workers are exposed to the chemical under four conditions of use that represent approximately 3% of the DINP production volume in the U.S. EPA found that workers are at risk if they are unprotected from the DINP contained in spray-applied adhesives and sealants, and paints and coatings. Spraying these products could create high concentrations of DINP in mist that an unprotected worker could inhale. EPA did not identify risk of injury to human health for consumers or the general population or the environment that would contribute to the unreasonable risk of DINP.

Background on DINP

DINP is a common chemical name for the category of chemicals that includes the following substances: 1,2-benzenedicarboxylic acid, 1,2-isononyl ester and 1,2-benzenedicarboxylic acid, and di-C9-11-branched alkyl esters, C9-rich. The primary use for DINP is as a plasticizer in plastic and rubber products. Information from the 2016 Chemical Data Reporting (CDR) for DINP indicates the reported production volume is between 200 and 500 million lbs/year (domestic manufacture including import).

Uses of DINP

In the final scope of the DINP risk evaluation, EPA identified conditions of use under TSCA associated with the manufacturing (including importing); processing; distribution in commerce; industrial, commercial and consumer uses; and disposal of DINP, including:

As a plasticizer in polyvinyl chloride (PVC);
In building and construction materials;
In automotive and fuel products; and
In other commercial and consumer products, including adhesives and sealants, paints and coatings, electrical and electronic products, and other plastic and rubber products.

The above listed conditions of use are ways that a person or the environment could be potentially exposed to DINP. However, when conducting a risk evaluation, EPA also considers the hazards (i.e., health effects or environmental impacts) that could occur from coming in contact with a chemical.

There are other uses of DINP that do not fall under TSCA, such as personal care products, cosmetics, and food contact materials.

Recent Activities and Opportunities for Public Comment

In January 2025, EPA released the final risk evaluation for DINP. EPA will now begin the risk management process to address the unreasonable risk presented by DINP. EPA will release a proposed rule under TSCA section 6 to protect workers from the identified risks.

In August 2024, EPA released the draft risk evaluation for DINP for public comment. EPA accepted public comment on the draft risk evaluation for 60 days following publication in the Federal Register. In May 2024, EPA released the draft physical chemical, fate, and hazard assessments for DINP for public comment and peer review. EPA accepted public comments on the draft documents for 60 days following publication in the Federal Register via docket EPA-HQ-OPPT-2024-0073 at www.regulations.gov.

EPA held a virtual peer review public meeting of the Science Advisory Committee on Chemicals (SACC) to discuss the draft risk evaluation documents from July 30 to August 1, 2024. EPA also held a virtual preparatory public meeting on July 23, 2024, for the SACC and the public to consider and ask questions regarding the scope and clarity of the draft charge questions and areas of review. EPA did not develop charge questions for all aspects of the draft risk evaluation materials for DINP; instead, the agency asked the SACC to review specific scientific areas that need peer review. View the SACC website for more information on these meetings.

In August 2021, EPA published the final scope document outlining the hazards, exposures, conditions of use, and the potentially exposed or susceptible subpopulations the agency expects to consider in its risk evaluation. The agency released the draft scope in November 2020 and took public comments on the draft document.

As EPA begins the TSCA risk management process, there will be additional opportunities for public comment, including a public comment period on the draft risk evaluation. In addition to multiple public comment periods, EPA will continue to engage with stakeholders as it develops the risk evaluation, and stakeholders should reach out to EPA via the staff contact to engage with the agency.

Supporting Documents

Read the Federal Register notice.

View the supporting documents in docket EPA-HQ-OPPT-2018-0436.