H.R. 4325 — Clean Shipping Act of 2025

This section establishes a marine vessel fuel carbon intensity standard under the Clean Air Act, requiring the EPA Administrator to promulgate regulations that mandate vessels of 400 gross tons or more on covered voyages—defined as commercial passenger or cargo transport between U.S. ports or between a U.S. port and a foreign port—to use fuel with lifecycle greenhouse gas emissions (measured in grams of carbon dioxide-equivalent per megajoule) that achieve the following reductions from a 2027 baseline (average carbon intensity of fuel used on such voyages): (1) at least 30% less in 2030 through 2034; (2) at least 58% less in 2034 through 2039; (3) at least 83% less in 2040 through 2044; (4) at least 92% less in 2045 through 2049; and (5) 100% less in 2050 and thereafter. The Administrator must finalize the 2030-2034 standard by January 1, 2029, and subsequent standards two years before they apply; if a reduction is not technologically or economically feasible, the Administrator must set the maximum feasible reduction instead, considering net emissions reductions and impacts on health, safety, air and water quality, and waste; the Administrator may harmonize with equal or stricter International Maritime Organization standards, exempt vessels on covered voyages 30 days or fewer annually, allow averaging across commonly owned or controlled vessels, and credit overcompliance toward future years. This section further directs the Administrator to develop consistent monitoring methods (aligned with EU and IMO schemes where practicable) and requires annual reporting by vessel owners or operators of fuel carbon intensity, usage, and total emissions per covered voyage, with the Administrator to issue an annual report 180 days after each period.

This section establishes zero-emission standards for greenhouse gases and criteria air pollutants (i.e., those for which air quality criteria have been issued under Clean Air Act §108) from vessels at anchorage or berth in the U.S. contiguous zone, requiring the EPA Administrator to promulgate such standards by January 1, 2029, with full compliance by January 1, 2035. If zero-emission standards are not technologically or economically feasible, the Administrator must instead promulgate standards achieving the maximum feasible reduction, considering net emission reductions and potential adverse impacts on public health, safety, air and water quality, and solid waste generation and disposal.