Diesel Fuel Standards and Rulemakings

• Overview
• Onroad (highway) diesel fuel standards
• Nonroad diesel fuel standards
• International fuel standards for Emission Control Areas (ECAs)  
• Diesel fuel related rulemakings
• Diesel fuel supporting documents

EPA is proposing a technical correction to the diesel fuel regulations to allow U.S. fuel manufacturers and distributors to sell distillate diesel fuel that complies with the global sulfur standard that applies internationally. See link below for more information on the proposal and instructions on how to submit comments.

Overview of Diesel Standards

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 in diesel fuel to 15 ppm. This fuel is known as ultra-low sulfur diesel (ULSD). 

• Onroad (or highway) vehicles; and
• Nonroad engines and equipment.

Collectively, diesel standards reduce harmful emissions from both onroad and nonroad diesel sources by more than 90%.

Onroad (Highway) Diesel Fuel Standards

From 2006 to 2010, ULSD was phased in for onroad diesel.

• All highway diesel fuel supplied to the market be ULSD; and
• All highway diesel vehicles must use ULSD.

• Regulations for emissions from commercial trucks and buses

Nonroad Diesel Fuel Standards

From 2007 to 2014, low sulfur diesel fuel (specified at 500 ppm) and ULSD fuel was phased in for nonroad, locomotive, and marine (NRLM) diesel fuel.

• 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).

• Regulations for emissions from heavy equipment with compression-ignition (diesel) engines
• Regulations for emissions from locomotives
• Domestic regulations for emissions from marine compression-ignition (diesel) engines

International Fuel Standards for Emission Control Areas (ECAs) and Global Marine Fuel

EPA is proposing changes to the regulations at 40 CFR part 80, subpart I, to allow for distribution and sale of distillate diesel fuel that complies with the 0.50 percent (5000 ppm) global sulfur standard contained in MARPOL Annex VI starting in 2020. These regulatory changes will accommodate the supply and distribution of distillate diesel fuel as global marine fuel.

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.

An international treaty designated two Emission Control Areas (ECA) covering U.S. waters. The North America ECA extends 200 miles from the shores of North America, and the U.S. Caribbean Sea ECA covers waters around Puerto Rico and the U.S. Virgin Islands.  The sulfur content of the fuel used in marine vessels operating in these ECAs may not exceed 0.10 weight percent (1000 ppm).

Note that a global sulfur cap of 3.50 weight percent applies outside of ECA boundaries. This limit decreases to 0.50 weight percent in 2020.

• Proposed Amendments Related to Marine Diesel Engine Standards
• International standards to reduce emissions from marine diesel engines and their fuels

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Diesel Fuel Related Rulemakings

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

• Regulations;
• Regulatory impact analyses;
• Comment summaries;
• Rule histories (including proposed rules); and
• Fact sheets.

Diesel Fuel Related Supporting Documents

• Supporting documents for Diesel Fuel Standards.