• EPA determines significant new uses through rulemakings on a chemical-by-chemical basis after considering all relevant factors.
• Persons who intend to export a substance identified in a proposed or final SNUR are subject to the export notification provisions of TSCA section 12(b).

Chemical manufacturers (including importers) and processors must submit a notice to the Environmental Protection Agency (EPA) before manufacturing or processing a chemical for a use that EPA has determined to be significant and new. EPA determines significant new uses through rulemakings on a chemical-by-chemical basis after considering all relevant factors, including:

• Projected volume of manufacturing and processing of a chemical substance;
• Extent to which a use changes the type or form of exposure of humans or the environment to a chemical substance;
• Extent to which a use increases the magnitude and duration of exposure of humans or the environment to a chemical substance; and
• Reasonably anticipated manner and methods of manufacturing, processing, distribution in commerce, and disposal of a chemical substance.

Although most significant new use determinations are associated with new chemicals, EPA has determined that certain non-ongoing uses (i.e., discontinued uses) are new uses for specific existing chemicals. EPA generally determines that a discontinued use of an existing chemical is a significant new use for which notification is required when a manufacturer or processor seeks to reintroduce such discontinued use of the existing chemical into commerce. This notification is intended to give the agency an opportunity to prevent the reintroduction of a discontinued use of an existing chemical if such a reintroduction would pose unreasonable risks. As an example, in April 2019, EPA determined that “any discontinued uses of asbestos cannot re-enter the marketplace without EPA review.”

Rulemaking prompts notifications

When EPA determines significant new uses, the rulemakings the agency issues are known as significant new use rules (SNURs). SNURs create regulations that appear at 40 CFR 721. This prompts three types of notifications:

• Significant new use notice (SNUN) — The notifications submitted by chemical manufacturers, importers, and processors under a SNUR are known as significant new use notices (SNUNs). Toxic Substances Control Act (TSCA) section 5 directs EPA to review a SNUN within 90 days of receipt to determine if regulatory action is warranted. EPA may extend the review period up to 90 days with appropriate justification. EPA promulgates multiple SNURs per year, but the agency does not receive, and generally does not expect, many SNUN submissions per year, based on prior experience. Promulgation of a SNUR does not imply EPA would approve the significant new uses of a chemical reported in a SNUN if the agency were to receive one. EPA does not predetermine the outcome of a SNUN review when promulgating a SNUR.
• Customer notification — Manufacturers (including importers) and processors of chemical substances subject to SNURs must also notify recipients of such chemicals of the SNUR or verify that knowledge of the SNUR has been otherwise acquired by recipients, or that the recipients are unable to engage in significant new uses. Since it is not expected that all such entities will have complete knowledge of all uses of any products subject to a SNUR, and because filing a SNUN could require significantly more burden, it is assumed that manufacturers (including importers) and processors will most often choose to notify their customers of SNUR regulatory activities. Notification may be accomplished by simply annotating and sending a safety data sheet (SDS).
• Export notification — Persons who intend to export a substance identified in a proposed or final SNUR are subject to the export notification provisions of TSCA section 12(b), and regulations that interpret TSCA section 12(b) appear at 40 CFR 707.