On December 7, 2007, EPA released an Advance Notice of Proposed Rulemaking (ANPRM) to encourage full participation in the development process of a rulemaking for new marine compression-ignition engines with per cylinder displacement at or above 30 liters (called Category 3 marine diesel engines). The comment period officially remained open through March 6, 2008. Many comments were received during that period, and others were received beyond that, through stakeholder outreach. On June 26, 2009, the Administrator signed a Notice of Proposed Rulemaking (NPRM) for proposed emission standards for new Category 3 marine diesel engines installed on U.S. vessels, under section 213 of the Clean Air Act (CAA or the Act). In that notice, we also proposed a change to our diesel fuel program. On July 1, 2009, this NPRM and supporting documentation was posted on EPAs web site. On that day a message was sent to interested stakeholders notifying them of the availability of this material for review and comment. On August 28, 2009, the NPRM was published in the Federal Register. This rule is part of a coordinated strategy to ensure that all ships that affect U.S. air quality meet stringent NOX and fuel sulfur requirements. We held two public hearings on the NPRM; one in New York, New York on August 4, 2009 and one in Long Beach, California on August 6, 2009. At those hearings, oral comments on the NPRM were received and recorded. A written comment period remained open until September 28, 2009. A complete list of organizations and individuals that provided comments on the NPRM is contained in the following table. Abbreviations for the organization names are also included. This Summary and Analysis of Comments contains a detailed summary of all comments we received on the NPRM as well as our analysis of each comment and our response. The reader should also refer to the final rulemaking notice in the Federal Register as well as the Final Regulatory Impact Analysis.