EPA’s Draft Risk Evaluation of DINP Finds Minimal Risks, but Determines That the Phthalate Presents an Unreasonable Risk
On August 30, 2024, EPA released its draft risk evaluation for diisononyl phthalate (DINP). The draft risk evaluation determined that most uses of DINP under the Toxic Substances Control Act (TSCA) “do not pose risk to the environment or the general population.”
The draft only identified three uses that “raise concerns” out of 47 evaluated conditions of use. However, EPA preliminarily found that DINP presents an unreasonable risk of injury to human health due to the agency’s “single risk determination” approach to risk evaluations.
Two of these three uses were found to raise concerns for workers: industrial use of adhesives and sealants and industrial use of paints and coatings, specifically in scenarios in which unprotected workers used high-pressure sprayers. According to the draft, these uses could create high concentrations of DINP in mist that an unprotected worker could inhale.
The other use—use of DINP in construction and building materials that cover large surface areas—was found to raise concerns for consumers. This use could result in young children inhaling DINP-containing dust that settles “onto vinyl flooring, in-place wallpaper, and carpet backing and [is] resuspended into the indoor environment,” the draft says.
The draft risk evaluation identified developmental toxicity and liver damage as potential health effects of these types of exposures. DINP also has the potential to cause “phthalate syndrome,” a collection of adverse effects on the developing male reproductive system, EPA said.
According to EPA, DINP is primarily used as a plasticizer to manufacture flexible polyvinyl chloride, better known as PVC. Data from the Chemical Data Reporting rule indicates that hundreds of millions of pounds of DINP are manufactured annually.
EPA initiated the risk evaluation process after a 2019 request from ExxonMobil Chemical Company to review DINP and its chemical relative diisodecyl phthalate (DIDP). EPA only found one concerning condition of use in DIDP’s draft risk evaluation, which was released this May.
DINP is a category of chemical substances which include 1,2-benzene-dicarboxylic acid, 1,2-diisononyl ester (CASRN 28553-12-0) and 1,2-benzenedicarboxylic acid, di-C8-10-branched alkyl esters, C9-rich (CASRN 68515-48-0).
Amended TSCA requires EPA to issue a risk management rule to address any unreasonable risks found by the final evaluation. Comments on the draft risk evaluation are due on November 4, 2024.
