This legislative proposal, known as the Clean Shipping Act of 2025, seeks to amend the Clean Air Act by introducing significant new environmental standards for the maritime sector. Its primary goal is to reduce greenhouse gas emissions from vessels operating in and around U.S. waters, addressing both fuel carbon intensity during voyages and direct emissions while in port. The Environmental Protection Agency (EPA) Administrator is tasked with developing and enforcing these new regulations.

The bill establishes a Marine Greenhouse Gas Fuel Standard, requiring a progressive reduction in the carbon intensity of fuel used by vessels of 400 gross tonnage or more on covered voyages. These voyages include those between U.S. ports or between a U.S. port and a foreign port. The standard mandates a 30 percent reduction from the 2027 baseline by 2030, escalating to a 100 percent reduction by 2050, effectively requiring zero carbon intensity. The EPA must consider technological and economic feasibility, allowing for adjustments if the set targets are not achievable.

Furthermore, the legislation introduces In-Port Marine Vessel Zero Emission Standards, directing the EPA to promulgate regulations by January 1, 2029. These standards aim to eliminate all greenhouse gas and air pollutant emissions from vessels at anchorage or berth in the U.S. contiguous zone by January 1, 2035. Similar to the fuel standard, the EPA can adjust these requirements based on technological and economic feasibility, ensuring the maximum possible reduction.

To ensure compliance and transparency, the bill mandates comprehensive monitoring and reporting requirements for vessel owners and operators. They must annually report on fuel carbon intensity, fuel usage, and total greenhouse gas emissions for all covered voyages. The EPA, in consultation with the Department of Transportation and the Coast Guard, will then publish a publicly accessible annual report compiling this data and explaining the emissions and carbon intensity of vessels.