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

In December 2025, EPA released the final 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). EPA designated DIBP as a High-Priority Substance in December 2019.

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

On this page:

• What is DIBP?
• Risk Evaluation
• Risk Evaluation and Supporting Documents
• Draft Risk Evaluation and Supporting Documents

What is 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).

Risk Evaluation

EPA determined that DIBP presents unreasonable risk of injury to human health based on risk to workers from four conditions of use (COU) and that DIBP presents an unreasonable risk to the environment from seven COUs. EPA did not identify a risk of injury to human health or the environment from the other 19 COUs for DIBP. For COUs with unreasonable risk to workers, these risk determinations do not reflect the use of personal protective equipment (PPE); however, as the risk evaluation shows, the use of PPE may reduce exposures and mitigate risk. EPA did not determine unreasonable risk of injury to human health for consumers or the general population for DIBP from any COU.   

Risk Evaluation and Supporting Documents

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

• Risk Evaluation for Diisobutyl Phthalate(DIBP) (pdf) (3.67 MB)
• Nontechnical Summary of the TSCA Risk Evaluation for Diisobutyl Phthalate (DIBP) (pdf) (221.04 KB)
• Physical Chemistry and Fate and Transport Assessment for Diisobutyl Phthalate (DIBP) (pdf) (751.52 KB)
• Environmental Release and Occupational Exposure Assessment for Diisobutyl Phthalate (DIBP) (pdf) (4.47 MB)
• Consumer and Indoor Exposure Assessment for Diisobutyl Phthalate (DIBP) (pdf) (2.78 MB)
• Environmental Media and General Population Exposure and Environmental Exposure for Diisobutyl Phthalate (DIBP) (pdf) (2.37 MB)
• Environmental Hazard Assessment for Diisobutyl Phthalate (DIBP) (pdf) (1.11 MB)
• Non-cancer Human Health Hazard Assessment for Diisobutyl Phthalate (DIBP) (pdf) (2.05 MB)
• Cancer Human Health Hazard Assessment for Di(2-ethylhexyl) Phthalate (DEHP), Dibutyl Phthalate (DBP), Butyl Benzyl Phthalate (BBP), Diisobutyl Phthalate (DIBP), and Dicyclohexyl Phthalate (DCHP) (pdf) (2.98 MB)
• Consumer Exposure Analysis for Diisobutyl Phthalate (DIBP) (xlsx) (3.39 MB)
• Ambient Air Exposure Assessment for Diisobutyl Phthalate (DIBP) (xlsx) (84.26 KB)
• Technical Support Document for the Cumulative Risk Analysis of Di(2-ethylhexyl) Phthalate (DEHP), Dibutyl Phthalate (DBP), Butyl Benzyl Phthalate (BBP), Diisobutyl Phthalate (DIBP), Dicyclohexyl Phthalate (DCHP), and Diisononyl Phthalate (DINP) Under the (pdf) (4 MB)
• Summary of and Response to External Peer Review on the Risk Evaluations and Technical Support Documents for Di(2-ethylhexyl) Phthalate (DEHP), Dibutyl Phthalate (DBP), Butyl Benzyl Phthalate (BBP), Diisobutyl Phthalate (DIBP), Dicyclohexyl Phthalate (DCH (pdf) (1.03 MB)
• Response to Public Comments on the Draft Risk Evaluations for Butyl Benzyl Phthalate (BBP); Dibutyl Phthalate (DBP); Dicyclohexyl Phthalate (DCHP); Diethylhexyl Phthalate (DEHP); and Diisobutyl Phthalate (DIBP) (pdf) (2.11 MB)

Additional technical support files for the Risk Evaluation of DIBP (zip) .

Draft Risk Evaluation and Supporting Documents

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). For more information, please visit the draft risk evaluation webpage.