On this page:

• Highway and nonroad diesel fuel standards
• Large marine diesel fuel standard in Emission Control Areas (ECAs)  
• Diesel fuel related rulemakings
• Diesel fuel supporting documents

Highway and Nonroad Diesel Fuel Standards

Highway Diesel Program -- a 15 parts per million (ppm) sulfur specification, known as ultra-low sulfur diesel (ULSD), was phased in for highway diesel fuel from 2006-2010.

Nonroad Diesel Program -- low sulfur (500 ppm) and ULSD (15 ppm) fuel was phased in for nonroad, locomotive, and marine (NRLM) diesel fuel from 2007-2014.

Before EPA began regulating sulfur in diesel, diesel fuel contained as much as 5,000 parts per million (ppm) of sulfur. EPA began regulating diesel fuel sulfur levels in 1993.  Beginning in 2006, EPA began to phase-in more stringent regulations to lower the amount of sulfur to 15 ppm. This fuel is known as ultra-low sulfur diesel (ULSD). 

EPA’s diesel program standards require that:

• After 2010, all highway diesel fuel supplied to the market be ULSD and all highway diesel vehicles must use ULSD
• After 2014, all nonroad, locomotive, and marine (NRLM) diesel fuel must be ULSD, and all NRLM engines and equipment must use this fuel (with some exceptions for older locomotive and marine engines)

These standards reduce harmful emissions from highway vehicles and nonroad engines and equipment by more than 90%.

Diesel Boats and Ships page.

Large Marine Diesel Fuel Standards in Emission Control Areas (ECA)

Ocean-going vessels and large ships traditionally used “bunker fuel” with sulfur levels as high as 5%, or 50,000 ppm, sulfur.  Bunker fuel burned on these ships was a large source of harmful air pollution in the U.S. 

Under an international treaty through the International Maritime Organization, EPA and the U.S. Coast Guard established two Emission Control Areas (ECA). One for North America that extends 200 miles from the shores of North America, and one for Puerto Rico and the U.S. Virgin Islands.  Beginning in 2015, large marine diesel engines propelling large ships and ocean-going vessels (Category 3 Engines) operating within the ECAs must generally use fuel with 1,000 ppm sulfur or less.

This limit is estimated to result in the following emissions reductions from ships operating in an ECA when compared to no regulations. 

• Nitrogen oxide emissions will drop 23 percent
• Particulate matter emissions will drop by 74 percent
• Sulfur oxide emissions will drop by 86 percent

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Diesel Fuel Related Rulemakings

For additional information on vehicles and fuel requirements, please see the following rulemakings:

• Highway Diesel Final Rule (66 FR 5002, January 18, 2001)
• Nonroad Diesel Final Rule Modifications to the Transmix Provisions under the Diesel Sulfur Program (77 FR 75868, December 26, 2012)
• Final Rule to Control the Emissions of Air Pollution from Nonroad Diesel Engines and Fuel (69 FR 38958, June 29, 2004)
• Fuel-Related Technical Amendments to the Highway and Nonroad Diesel Rules (70 FR 40889, July 15, 2005; 70 FR 70498, November 22, 2005; 79 FR 29816, May 21, 2013; 71 FR 25706, May 1, 2006) 
• Ocean-going Vessels Category 3 Marine Rule (75 FR 22896, April 30, 2010)
• Tier 3 Vehicle Emission and Fuel Standards Program 2015 Amendments Direct Final Rule (80 FR 9078, February 19, 2015) 

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Diesel Fuel Related Supporting Documents

For more information, review diesel fuel supporting documents.

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