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EPA Releases Final Scope Documents for Manufacturer-Requested Risk Evaluations of DIDP and DINP

WASHINGTON (August 31, 2021) - Today, EPA is releasing final scope documents for Toxic Substances Control Act (TSCA) risk evaluations of diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP). Both DIDP and DINP belong to a family of chemicals called phthalates and are commonly used as plasticizers in the production of plastic and plastic coating to increase flexibility.

The final scope documents reflect EPA’s policy changes on risk evaluations announced in June. This includes plans to consider exposure pathways that may be regulated outside of TSCA, like air and water, and potential for exposures to fenceline communities (i.e., communities near industrial facilities). Assumptions that personal protective equipment (PPE) in occupational settings will always be properly utilized will not be used as the basis for the risk determination. Use of PPE, and other ways industry protects its workers, will be assessed during the risk evaluation and considered as potential ways to address unreasonable risks during the risk management process. Going forward, risk evaluations of existing chemicals, including DIDP and DINP, will ensure unreasonable risks from chemicals are assessed in a way that is supported by science and the law.

The final scope documents released today explain EPA’s plan for the risk evaluations, including the conditions of use, hazards, exposures, and the potentially exposed or susceptible subpopulations EPA will consider in the risk evaluations. The documents also include: a description of the reasonably available information and the best available science approaches that the agency will use, a conceptual model that outlines the potential hazards and exposures throughout the life cycle of the chemical, an analysis plan to identify the approaches and methods EPA will use to assess health and environmental risks, and a plan for peer review.

EPA used feedback received on the draft scoping documents during the public comment period to inform the final documents.

EPA granted manufacturer requests for risk evaluations for these chemical categories in December 2019, and released draft scope documents in November 2020. Manufacturer-requested risk evaluations are generally conducted in the same manner as other risk evaluations conducted under TSCA.

View the final scope document for DIDP.

View the final scope document for DINP.  

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Last updated on May 27, 2025
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