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Draft Scope Documents for Manufacturer-Requested Risk Evaluations of DIDP and DINP Available for Public Comment

For Release: November 25, 2020

EPA is asking for public input on the draft scope documents for 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 agency granted manufacturer requests for Toxic Substances Control Act (TSCA) risk evaluations for these chemicals and seeking public input on the draft scope documents, which include the conditions of use to be included in the risk evaluations, the next step in the process.

Manufacturer-requested risk evaluations are generally conducted in the same manner as other risk evaluations conducted under TSCA. The draft scope documents issued today include conditions of use, hazards, exposures, and the potentially exposed or susceptible subpopulations that the 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 is accepting comments on the draft scope documents for 45 days. Comments may be submitted to the dockets relevant to this action: EPA-HQ-OPPT-2018-0435 for DIDP and EPA-HQ-OPPT-2018-0436 for DINP. EPA will use feedback received from the public comment process to inform the final scope documents.

View the draft scope document for the risk evaluation of DINP.

View the draft scope document for the risk evaluation of DIDP.


Under TSCA, chemical manufacturers can request that EPA conduct a risk evaluation on a specific chemical. By giving manufacturers the opportunity to prioritize, identify, and request the evaluation of chemicals and conditions of use of interest to them, EPA is encouraging sensible and timely assessment of chemicals in the marketplace.

In May 2019, EPA received two manufacturer requests to conduct risk evaluations for these chemicals. EPA found the requests for DIDP and DINP facially complete on June 13, 2019. In August 2019, EPA asked for public comment on the two manufacturer requests and granted the requests on December 2, 2019.

Both DIDP and DINP were identified in the 2014 Update to the TSCA Work Plan. EPA is also assessing six other phthalates as part of the next 20 chemicals undergoing risk evaluation and has issued final scopes for those chemicals.

Learn more about manufacturer-requested risk evaluations.