This document amends the U.S. Customs and Border Protection (CBP) regulations regarding the requirement to file a Toxic Substances Control Act (TSCA) certification when importing into the customs territory of the United States chemicals in bulk form or as part of mixtures and articles containing a chemical or mixture. This document amends the regulations to establish an electronic option for importers to file the required U.S. Environmental Protection Agency (EPA) TSCA certifications, consistent with the Security and Accountability for Every Port Act of 2006. This document further amends the regulations to clarify and add certain definitions, and to eliminate the paper-based blanket certification process. The document was prepared in consultation with EPA, the agency with primary responsibility for implementing TSCA.