This document sets forth final amendments to the Customs Regulations regarding submission of an importer's certification in connection with the importation of chemical substances subject to the Toxic Substances Control Act. The regulatory amendments reduce the regulatory burden by permitting use of a blanket certification for multiple shipments in lieu of a separate certification for each individual shipment. The final regulations also continue the present practice of allowing some flexibility regarding presentation of the required certification with the entry documentation for an individual shipment.