Risk Evaluation for Diisobutyl Phthalate (1,2-Benzene- dicarboxylic acid, 1,2- bis-(2methylpropyl) ester) (DIBP)

In July 2025, EPA released the draft risk evaluation and associated technical support documents for diisobutyl phthalate (1,2-Benzene- dicarboxylic acid, 1,2- bis-(2methylpropyl) ester) (DIBP) under the Toxic Substances Control Act (TSCA) for public comment.

EPA designated DIBP as a High-Priority Substance in December 2019 and the chemical is currently undergoing risk evaluation.

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

On this page:

Risk Evaluation Findings
Background on DIBP
Conditions of Use of DIBP
Recent Activities and Opportunities for Public Comment
Draft Risk Evaluation and Supporting Documents

Risk Evaluation Findings

EPA is preliminarily determining that DIBP presents unreasonable risk of injury to human health based on risk to workers from two COUs and that DIBP presents an unreasonable risk to the environment from four COUs. EPA did not preliminarily identify a risk of injury to human health or the environment from the other 22 COUs for DIBP. For COUs with unreasonable risk to workers, these preliminary risk determinations do not reflect the use of personal protective equipment (PPE); however, as the draft risk evaluation shows, the use of PPE may reduce exposures and mitigate risk. EPA did not preliminarily determine unreasonable risk of injury to human health for consumers or the general population for DIBP from any COU.

Background on DIBP

DIBP (CASRN 84-69-5) is a colorless liquid. The primary use for DIBP is a plasticizer in adhesive and sealant manufacturing. Information from the 2016 Chemical Data Reporting (CDR) for DIBP indicates the reported production volume is less than 1,000,000 lbs/year (manufacture and import).

Conditions of Use of DIBP

In the final scope, EPA identified conditions of use associated with the importing; processing; distribution in commerce; industrial, commercial and consumer uses; and disposal of DIBP, for example:

In adhesives and sealants;
In paints and coatings;
In plastic and rubber products;
For laboratory chemicals; and
In commercial and consumer products, including adhesives and sealants, paints and coatings, plastic and rubber, dyes in fabric, textiles and leather and inks, toner and colorant.

The above listed conditions of use are ways that a person or the environment could be potentially exposed to this chemical. 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.

Recent Activities and Opportunities for Public Comment

In July 2025, EPA released the draft risk evaluation for public comment. Upon publication of a Federal Register notice, EPA will accept comments for 60 days via docket EPA-HQ-OPPT-2018-0434 on regulations.gov. Although EPA’s Science Advisory Committee on Chemicals (SACC) will not peer review the draft risk evaluation for DIBP, it is reviewing the draft risk evaluations for dibutyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP), and dicyclohexyl phthalate (DCHP), as well as several technical support documents that will support the risk evaluation for DIBP. The human health and environmental hazard assessment and physical chemical properties and environmental fate and transport technical support documents for DIBP are included in this SACC review. The exposure methodologies demonstrated in the Draft Risk Evaluation for DBP, DCHP, and DEHP will be applicable to DIBP exposure scenarios. EPA will consider the SACC recommendations from this upcoming peer review when developing the risk evaluations and unreasonable risk determinations for these two chemicals. Therefore, EPA does not expect the need for an additional peer review of the risk evaluation for DIBP.

In August 2020, EPA published a 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 April 2020 and took public comments on the draft document.

Read the final scope of the risk evaluation for this chemical and EPA’s response to comments on the draft scope.
View the docket for this chemical, EPA-HQ-OPPT-2018-0434 on regulations.gov.

In addition to public comment periods, EPA will continue to engage with stakeholders as it refines the risk evaluation and stakeholders should reach out to EPA via the staff contact to engage with the agency.

Draft Risk Evaluation and Supporting Documents

View the supporting documents for EPA-HQ-OPPT-2018-0434.