This document amends the Customs Regulations, in conformance with regulations of the U.S. Environmental Protection Agency (EPA), in order to include marine spark-ignition engines among those imported nonroad engines that are subject to compliance with applicable EPA emissions standards required by law. In addition, the Customs Regulations in this regard are further amended by eliminating the unnecessary, extensive replication of the particular admission requirements for subject nonroad engines that are already contained in the EPA regulations.