A January 2003 final rule established the first U.S. emission standards for new compression-ignition Category 3 marine engines, those with a displacement at or above 30 liters per cylinder displacement. It also established a deadline of April 27, 2007 for EPA to promulgate a new tier of emission standards for these engines as determined appropriate under Clean Air Act (CAA) section 213(a). This rulemaking schedule was intended to allow EPA time to consider the state of technology that may permit deeper emission reductions and the status of international action for more stringent standards. Since 2003, we have continued to gain a greater understanding of the technical issues described in the final rule and to assess the continuing efforts of manufacturers to apply advanced emission control technologies to these very large engines, through ongoing discussions with various stakeholders. In addition, we have continued to work with and through the International Maritime Organization (IMO) toward more stringent international emission standards that would apply to all new marine diesel engines on ships engaged in international transportation. IMO is an important forum for EPA to gather new information and data regarding emission control technologies, costs, and other information on Category 3 engines and vessels. IMO is also important because the majority of ships used in international commerce are flagged in other nations. Due to the length of time necessary to assess advanced emission control technologies much of the information that we believe is necessary to develop more stringent Category 3 marine diesel engines standards has only become available recently and we expect more information to come to light in the course of the current negotiations underway at the IMO. Therefore, EPA is adopting a new deadline for the rulemaking that will consider the next tier of Category 3 marine diesel engine standards. Under this new schedule, EPA would adopt a final rule by December