On January 14, 2025, the EPA released the final risk evaluation for diisononyl phthalate (DINP), which was conducted under the Toxic Substances Control Act (TSCA). The EPA concluded that DINP presents an unreasonable risk of injury to human health because workers could be exposed to high concentrations of DINP in mist when spraying adhesive, sealant, paint, and coating products that contain DINP.

Andrewshots / Shutterstock.com

DINP is used as a plasticizer to make flexible polyvinyl chloride (PVC) and to make building and construction materials, automotive articles, and other commercial and consumer products, including adhesives and sealants, paints and coatings, and electrical and electronic products.

Its use has been linked to developmental toxicity and harm to the liver. It can also cause cancer at higher rates of exposure and can harm the developing male reproductive system.

“EPA conducted the risk evaluation for DINP at the manufacturer’s request,” according to an Agency news release. “Under TSCA, manufacturers can request that EPA conduct risk evaluations on chemicals they manufacture. EPA received and granted this manufacturer request for a risk evaluation of DINP in 2019.

“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.”

Some analysts believe the risk determination is flawed.

“EPA, however, does not explain that its conclusion is based on its assumption that workers are not protected,” notes a JD Supra article by Bergeson & Campbell P.C. “Taken literally, EPA’s statement is that all such workers are at risk, not just unprotected workers. This may seem trivial, but words matter, especially those written by EPA. EPA may wish going forward to be a bit more deliberate in framing its bottom-line conclusion and clearly communicate to the public, especially workers, what the risks are and the importance of following the hierarchy of controls, including using respiratory protection, all without unduly alarming workers or the public.”

Once the EPA determines that a chemical presents an unreasonable risk to health or the environment, the chemical must immediately move to risk management action under TSCA. At that point, the Agency is required to implement regulatory restrictions on the manufacture, processing, distribution, use, or disposal of the chemical to eliminate the unreasonable risk.

The EPA is given a range of risk management options under TSCA, including:

• Labeling
• Recordkeeping or notice requirements
• Actions to reduce human exposure or environmental release
• Banning the chemical entirely or banning certain uses

Like the prioritization and risk evaluation processes, there’s an opportunity for public comment on any proposed risk management actions.

However, the new administration is currently reviewing final sunset actions that occurred under the previous administration, meaning unexpected changes may occur with this risk determination.