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EPA Proposes High Priority Substances under TSCA

On August 23, 2019, EPA published a notice proposing 20 chemicals as high priority substances under the Toxic Substances Control Act (TSCA). Comments on the proposed designations must be received by November 21, 2019.

The 20 chemicals include seven chlorinated solvents, five phthalates, three halogenated flame retardants, and five other chemicals including formaldehyde. EPA also has published supporting materials for its proposed designations, which include reviews of the substances’ production volumes, conditions of use, potentially exposed populations, persistence and bioaccumulation, storage near significant sources of drinking water, hazard potential, and exposure potential. The supporting materials ultimately summarize the agency’s rationale for the proposed designation. For di(2-ethylhexyl) phthalate (DEHP), for example, EPA explains:

EPA identified and analyzed reasonably available information and concluded that DEHP may present an unreasonable risk of injury to health and/or the environment, including potentially exposed or susceptible subpopulations, (e.g., workers, consumers, women of reproductive age, children). This is based on the potential hazard and potential exposure of DEHP under the conditions of use described in this document to support the prioritization designation. Specifically, EPA expects that the manufacturing, processing, distribution, use, and disposal of DEHP may result in presence of the presence of the chemical in surface water and in groundwater, ingestion of the chemical in drinking water, inhalation of the chemical from air releases, exposure to workers, exposure to consumers, and exposure to the general population, including children. In addition, EPA expects potential environmental (e.g., aquatic toxicity, terrestrial toxicity) and human health hazards (e.g., repeated dose toxicity, reproductive toxicity, developmental toxicity, carcinogenicity, neurotoxicity, and observations in epidemiologic and/or biomonitoring studies).

EPA’s designations of high priority substances are required under the 2016 TSCA amendments, pursuant to which the agency must formally identify 20 chemical substances as high priority substances by December 2019.

High priority substances are chemicals that EPA determines, without consideration of costs or other non-risk factors, may present an unreasonable risk of injury to human health or the environment. When a chemical proposed for such designation is finally, formally identified as a high priority substance, EPA must undertake a risk evaluation pursuant to which the agency will make a formal determination of whether the substance does present an unreasonable risk of injury to human health or the environment. If EPA determines that a high priority substance presents an unreasonable risk, it is authorized to regulate the substance by, for example, limiting the manufacture, distribution or use of the substance, or even prohibiting it.


Grimaldi Law Offices has been advising clients for over 20 years on chemical and product regulation. For knowledgeable advice and in-depth analysis on your chemical regulatory compliance obligations, contact Grimaldi Law Offices at (415) 463-5186 or email us at [email protected].

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Ms. Grimaldi maintains a diverse environmental law practice focusing on chemical and product regulation and litigation defense. Her practice areas include Proposition 65, California's Safer Consumer Products Regulations, California's Rigid Plastic Packaging Container Act and the federal Toxic Substances Control Act. Ms. Grimaldi graduated from the University of California Hastings College of the Law magna cum laude and holds a Bachelor of Science Degree in Bacteriology from University of California, Davis. Prior to attending law school, she worked as a research assistant in laboratories at the University of California, San Francisco Cancer Research Institute and at the University of California, San Francisco School of Medicine.