10 December 1998

The US EPA proposed a national program to control emissions of oxides of nitrogen (NOx) and particulate matter (PM) from large marine diesel engines. The Agency published a Notice of Proposed Rulemaking (NPRM) that includes the proposed regulatory language. This action is a next step towards finalizing the marine engine regulations after the publication of an Advanced Notice of Proposed Rulemaking in May 1998.

The proposed regulations cover marine diesel engines of above 37 kW (50 hp) that are used for propulsion and auxiliary power on commercial vessels in a variety of marine applications, including fishing boats, tug and towboats, dredgers, coastal and Great Lakes cargo vessels, and ocean going vessels. Engines for recreational vessels will be covered by a separate rulemaking action.

Emissions from marine diesel engines account for about 4.5% of total mobile source NOx emissions nationwide and about 1% of PM emissions. However, because of the nature of their operation, the contribution of these engines to total NOx emissions in port cities and coastal areas is higher. If the proposed regulations are implemented, EPA estimates a 34% reduction in NOx emissions and a 14% reduction in PM emissions in 2030 when the program is fully phased-in.

Three sets of provisions have been proposed. First, a two-phase emission control strategy is set out for marine diesel engines that are derived from land-based nonroad or locomotive engines. The first phase would go into effect in 2004/2006, depending on engine size. The second phase would go into effect in 2008/2010, but will be subject to a feasibility review in 2003. Larger engines would be required to meet the emission limits finalized by the International Maritime Organization (IMO). The IMO limits would also apply to the smaller engines prior to 2004.

Second, the EPA proposes a new approach for controlling off-cycle emissions, and calls for engine manufacturers to demonstrate compliance with the emission limits over a variety of operating conditions. These off-cycle requirements would become effective with the 2004/2006 emission limits. Finally, the certification and compliance provisions being considered are derived from the programs for land-based nonroad or locomotive engines, but will reflect unique characteristics of the marine derivatives of these engines.

EPA will hold a pubic hearing in January 1999 and will accept written comments on the NPRM for 60 days after publication in the Federal Register, expected in December 1998.

The NPRM and related documents are available via the EPA Internet server at http://www.epa.gov/oms/marine.htm.

Source: US EPA
Contact: Alan Stout, 734-214-4805, stout.alan@epa.gov