EPA Releases Draft TSCA Risk Evaluation for Phthalate DIBP for Public Comment
Released July 31, 2025
Today, the U.S. Environmental Protection Agency released its draft risk evaluation for diisobutyl phthalate (DIBP) under the Toxic Substances Control Act (TSCA). EPA preliminarily determined that DIBP presents unreasonable risk of injury to human health and the environment under certain conditions of use (COUs).
DIBP Draft Risk Evaluation
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.
Read the draft risk evaluation for DIBP.
Next Steps
In the next few days, EPA will publish a Federal Register notice announcing the draft risk evaluation for DIBP. Upon publication of the Federal Register notice, EPA will accept public comments on the draft risk evaluation for DIBP via its TSCA docket EPA-HQ-OPPT-2018-0434 for 60 days. Please check the DIBP docket to view the Federal Register notice and deadline for submitting comments.
Although EPA’s Science Advisory Council 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 hazard, environmental hazard, and physical chemistry and fate and transport technical support documents for DIBP are included in this SACC review. The exposure methodologies demonstrated in the Draft Risk Evaluations for DBP, DCHP, and DEHP will be applicable to DIBP exposure scenarios. EPA will consider the SACC recommendations from this upcoming peer review when finalizing the risk evaluation and unreasonable risk determination for this chemical. Therefore, EPA does not expect the need for an additional peer review of the risk evaluation for DIBP.
After the agency has considered public comments and the independent, expert peer review, EPA will issue final risk evaluations that include its determination as to whether DIBP represents an unreasonable risk of injury to human health or the environment based on identified unreasonable risk from the COUs.