Nonroad Engines, Equipment, and Vehicles

Diesel Boats and Ships

Consumer Information

Emission Standards and Owner Responsibilities(4 pp, 158K, EPA-420-F-12-053, August 2012)
Requirements for Rebuilding Certified Engines (PDF) (4 pp, 143K, EPA-420-F-12-052, August 2012)
Boating Pollution Prevention Tips (PDF) (2 pp, 134K, EPA-420-F-13-006, January 2013)
Marinas & Boating
About the Clean Boating Act
Used Oil Management

Related Links

Emission Standards Reference Guide
Verify
Certification Tools
Engine Certification Information Center
Ocean Vessels and Large Ships
Nonroad Diesel Equipment (including Tier 1 and Tier2 standards for marine diesel engines < 37kW)
Gasoline Boats and Personal Watercraft
Certification Fees
Importing Vehicles and Engines
National Clean Diesel Campaign
Diesel Fuel
Clean Diesel Fuel Alliance

NOTE: You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.

Marine diesel engines are used in a variety of different types of vessels ranging in size and application from small recreational runabouts to large ocean-going vessels. New marine diesel engines must meet increasingly stringent emissions requirements, yet these engines continue to emit significant amounts of oxides of nitrogen (NOx) and particulate matter (PM), both of which contribute to serious public health problems.

In May 2004, as part of the Nonroad Diesel Tier 4 Rule, EPA finalized new requirements that decrease the allowable levels of sulfur in marine diesel fuel by 99 percent. These fuel improvements, which began to take effect in 2007, are creating significant environmental and public health benefits by reducing PM from new and existing engines.

In March 2008, EPA finalized a three-part program that further reduces emissions from marine diesel engines with per-cylinder displacement below 30 liters. These include marine propulsion engines used on vessels from recreational and small fishing boats to towboats, tugboats and Great Lake freighters, and marine auxiliary engines ranging from small generator sets to large generator sets on ocean-going vessels. The rule will cut PM emissions from these engines by as much as 90 percent and NOx emissions by as much as 80 percent when fully implemented.

The 2008 final rule includes the first-ever national emission standards for existing commercial marine diesel engines, applying to engines larger than 600kW when they are remanufactured (PDF) (7 pp, 160k, EPA_420-F-09-003, February 2009). The rule also sets Tier 3 emissions standards for newly built engines that are phasing in from 2009. Finally, the rule establishes Tier 4 standards for newly built commercial marine diesel engines above 600kW, based on the application of high-efficiency catalytic aftertreatment technology, phasing in beginning in 2014.

The Ocean Vessels and Large Ships page includes information on U.S. regulations for Category 3 marine diesel engines as well as the international treaty called MARPOL Annex VI with standards that apply for marine diesel engines over 130 kW. Information is also available on Gasoline Boats and Personal Watercrafts.

Regulations
Certification Guidance Documents
Emission Inventory Publications

Regulations

See the electronic Code of Federal Regulations (e-CFR) for the full text of current regulations that apply to marine diesel engines and vessels:

40 CFR part 1042	Emission Standards and Certification Requirements—Tier 3 and Tier 4
40 CFR part 94	Emission Standards and Certification Requirements—Tier 1 and Tier 2 for engines at or above 37 kW
40 CFR part 89	Emission Standards and Certification Requirements—Tier 1 and Tier 2 for engines below 37 kW
40 CFR part 1065	Engine Exhaust Emission Test Procedures
40 CFR part 1068	General Compliance Provisions
40 CFR part 1043	Regulations implementing MARPOL Annex VI, including requirements for in-use fuels, engines above 130 kW, and vessels with those engines

Summary of exhaust emission standards
2013 and 2014 Amendments (published June 17, 2013 and February 6, 2014)
- Fact Sheet : EPA Re-Issues Amendments for Nonroad Engines and Equipment (PDF) (2 pg, 130K, EPA-420-F-14-002, January 2014)
- Final Rule (PDF) (11 pp, 272K, published February 6, 2014)
- Partial Withdrawal of Direct Final rule (PDF) (5 pp, 296K, published August 16, 2013)
- Fact Sheet: EPA Issues Amendments to the Heavy-Duty Highway Greenhouse Gas Rule and Other Nonroad Provisions (PDF) (3 pp, 534K, EPA-420-F-13-001, May 2013)
- Direct Final Rule (PDF) (38 pp, 652K, published June 17, 2013)
2010 Amendments (published November 8, 2010)
- Final Rule (PDF) (20 pp, 366K)
- See Heavy-duty Highway Engines for more information.
Tier 2 and Tier 3 Emission Standards for Category 3 Marine Diesel Engine Standards (published April 30, 2010)
- See Ocean Vessels and Large Ships for the Final Rule and supporting documents.
Tier 3 and Tier 4 Emission Standards for Category 1 and Category 2 Marine Diesel Engines (published June 30, 2008)
- Fact Sheet: EPA Finalizes More Stringent Emissions Standards for Locomotive Engines and Marine Compression-Ignition Engines (PDF) (5 pp, 134K, EPA-420-F-08-004, March 2008)
- Final Rule (PDF) (255 pp, 2.08MB)
- Regulatory Impact Analysis
- Summary and Analysis of Comments (PDF) (463 pp, 2.31MB, EPA-420-R-08-006, March 2008)
- See the rulemaking docket for additional information
- See the Proposed Emission Standards for the proposed rule and supporting documents (published April 3, 2007).
Procedures for Testing Highway and Nonroad Engines and Omnibus Technical Amendments (published July 13, 2005)
- Fact Sheet: Regulatory Announcement: Changed Test Procedures for Nonroad Engines and Heavy-Duty Highway Engines (PDF) (4 pp, 134K, EPA420-F-05-036, July 2005)
- Final Rule (PDF) (193 pp, 7.48MB)
- Technical Support Document and Summary & Analysis of Comments (PDF) (115 pp, 712K, June 2005)
- See Proposed Technical Amendments for the proposed rule and supporting documents (published September 10, 2004).
Tier 1 Emission Standards for Marine Diesel Engines with per-Cylinder Displacement above 2.5 Liters (published February 28, 2003)
- See Ocean Vessels and Large Ships for the Final Rule and supporting documents.
Tier 2 Emission Standards for Recreational Marine Diesel Engines (published November 8, 2002)
- Fact Sheet: Emission Standards for New Nonroad Engines (PDF) (7 pp, 412K, EPA420-F-02-037, September 2002)
- Final Rule (PDF) (206 pp, 1.15MB)
- Regulatory Support Document (PDF) (687 pp, 2.6MB, EPA420-R-02-022, September 2002)
- Summary and Analysis of Comments (PDF) (319 pp, 1.07MB, EPA420-R-02-023, September 2002)
- Environmental Impacts of Newly Regulated Nonroad Engines (PDF) (5 pp, 24K, EPA420-F-02-033, September 2002)
- Docket Index (PDF) (141 pp, 690K, September 2002)
- See Proposed Emission Standards for the proposed rule, fact sheet and regulatory support documents (published October 5, 2001).
Tier 2 Emission Standards for Commercial Marine Diesel Engines (published December 29, 1999)
- Fact Sheet: Emission Standards for New Marine Commercial Engines (PDF) (2 pp, 9K, EPA420-F-99-043, November 1999)
- Final Rule (PDF) (74 pp, 508K)
- Regulatory Impact Analysis (132pp, 966K, EPA420-R-99-026, November 1999)
- Summary and Analysis of Comments (PDF) (94 pp, 410K, EPA420-R-99-028, November 1999)
- Docket Index (PDF) (29 pp, 52K, November 2000)
- In-Use Marine Diesel Fuel (PDF) (21 pp, 68K, EPA420-R-99-027, August 1999)
- Incremental Cost Estimates for Marine Diesel Engine Technology Improvements (PDF) (48 pp, 182K, EPA420-R-98-021, September 1998)
- Emission Standards for Marine Diesel Engines: Scope of Application (PDF) (4 pp, 16K, EPA420-F-00-006, February 2000)
- See Proposed Emission Standards for the proposed rule and supporting documents (published December 11, 1998).