• If EPA issues a proposed rule under TSCA section 5(f), the requirements in the proposed rule become effective upon its publication in the Federal Register.

If the Environmental Protection Agency (EPA) finds that a significant new use of a chemical substance subject to a significant new use notice (SNUN) presents an unreasonable risk, section 5(f) of the Toxic Substances Control Act (TSCA) directs the agency to either:

• Propose a rule imposing one or more of the requirements specified in section 6(a) to the extent necessary to protect against such risk, or
• Issue an order to prohibit or limit the manufacture, processing, or distribution of the chemical.

If EPA issues a proposed rule under section 5(f), the requirements in the proposed rule become effective upon its publication in the Federal Register, and EPA must, as expeditiously as possible, either finalize the rule (with or without modification) or revoke it. An issued order becomes effective at the end of the review period, which is 90 days unless extended to 180 days with good cause.

If EPA finds that available information is insufficient to evaluate risks of a new chemical substance or significant new use, section 5(e) requires EPA to issue an administrative order to prohibit or otherwise restrict manufacture, processing, distribution, use, or disposal to the extent necessary to protect against unreasonable risks pending the development of further information. An issued order becomes effective at the end of the review period. The submitter of the SNUN must comply with the order while the required information is being developed. For significant new uses for which information is insufficient to evaluate risks while section 5(e) orders apply to the SNUN submitter, EPA may in practice also promulgate a significant new use rule (SNUR) to apply the restrictions outlined in an order to other manufacturers and processors.

For substances subject to SNUN restrictions that EPA subsequently finds are not likely to present unreasonable risk; the submitter of the notice may commence manufacture of the substance for the uses described in the notice after the agency publishes a statement of its finding.

Orders related to importing

TSCA section 5(e) orders may include restrictions on the amount of the chemical allowed to be manufactured (including imported), as well as other restrictions. (The import/production limits often serve as triggers for toxicity or related testing requirements.) To comply with these requirements when applicable, chemical substances must:

• Not be imported for any prohibited use;
• Satisfy all applicable labeling and safety data requirements;
• Not exceed any specified restrictions on permissible import volume;
• Not be imported for any designated significant new use; and
• Comply with any other applicable requirements.