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Please note: This summary is provided to help you understand the regulations. Consult the references provided for links to the full text of the regulations.

Diesel Fuel Requirements (Truck) (2007 Highway Rule)

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In 2000, EPA introduced a new program referred to as the Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirements. There are two parts to the program:

  • New vehicle engine emission standards that began to take effect in model year 2007, which are based on the use of high-efficiency catalytic exhaust emission control devices or comparably effective advanced technologies.

  • New diesel fuel standards that reduced the level of sulfur in highway diesel fuel by 97% by mid-2006. The low sulfur diesel standards were necessary because the advanced air emissions equipment required for model year 2007 vehicles and engines, would otherwise be damaged by higher sulfur concentrations present in diesel fuel prior to the new fuel standard.

The Heavy-Duty Highway Rule is comparable to the 1970's catalytic converter regulatory program for cars. In that case, it was necessary to remove lead from gasoline to enable the use of catalytic converters.

Locomotives and ships also operate on diesel engines. In 2008, EPA passed new standards for these engines, including requirements for newly-built engines that are based on aftertreatment technology. These standards are enabled by the availability of ultra-low sulfur diesel fuel.

This section of TERC provides a brief overview of the 2007 Highway Rule and links to more detailed information.


Who is affected by the regulations?

The 2007 Highway Rule is directed at vehicle and engine manufacturers and the refining industry, who are required to produce cleaner running engines and diesel fuel. However, the benefits and costs and of the rules affect everyone. The benefits include lower air emissions and significant health improvements, as discussed below. The costs are felt at the pump in terms of higher fuel prices, which increase transportation costs. The U.S. Government has estimated that pump prices for diesel fuel increased between $0.05 and $0.25 per gallon as a result of the transition to low sulfur diesel.

What is the purpose of the regulations?

Diesel exhaust or diesel particulate matter (soot) is likely to cause lung cancer in humans. Other health effects include aggravation of respiratory and cardiovascular disease, aggravation of existing asthma, acute respiratory symptoms, chronic bronchitis and decreased lung function.

The move to lower sulfur content allows the application of newer emissions control technologies that substantially lower emissions of particulate matter from diesel engines. Once this action is fully implemented (i.e., approximately 2030, once new trucks and engines replace existing fleets) the following benefits are anticipated:

  • 2.6 million tons of smog-causing nitrogen oxide emissions will be reduced each year.
  • Soot or particulate matter will be reduced by 110,000 tons a year.
  • An estimated 8,300 premature deaths, 5,500 cases of chronic bronchitis and 17,600 cases of acute bronchitis in children will be prevented annually.
  • An estimated 360,000 asthma attacks and 386,000 cases of respiratory symptoms in asthmatic children will also be avoided every year.
  • 1.5 million lost work days, 7,100 hospital visits and 2,400 emergency room visits for asthma will be prevented.


Standards for Heavy-Duty Highway Engines and Vehicles. The standards for heavy-duty highway vehicles and engines are found at 40 CFR 86.007-11. These rules require vehicle/engine manufacturers to meet particulate matter (PM) emissions standard for new heavy-duty engines of 0.01 grams per brake-horsepower-hour (g/bhp-hr), to take full effect for diesels in the 2007 model year. They are also required to meet standards for oxides of nitrogen (Nox) and non-methane hydrocarbons (NMHC) of 0.20 g/bhp-hr and 0.14 g/ bhp-hr, respectively. The Nox and NMHC standards were phased in together between 2007 and 2010. The phase-in was based on a percent of- sales basis: 50 percent from 2007 to 2009 and 100 percent in 2010.

Standards for Diesel Fuel. The regulations for diesel fuel are found at 40 CFR 80.500. The standards, required refiners to start producing diesel fuel for use in highway vehicles with a sulfur content of no more than 15 parts per million (ppm), beginning June 1, 2006. At the terminal level, highway diesel fuel sold as low sulfur fuel was required to meet the 15 ppm sulfur standard as of July 15, 2006. For retail stations and fleets, highway diesel fuel sold as low sulfur fuel had to meet the 15 ppm sulfur standard by September 1, 2006.

This program included a combination of flexibilities available to refiners to ensure a smooth transition to low sulfur highway diesel fuel. Refiners could take advantage of a temporary compliance option, including an averaging, banking and trading component, beginning in June 2006 and lasting through 2009, with credit given for early compliance before June 2006.

Standards for Locomotive and Marine Diesel Engines. Sources of diesel emissions, other than trucks are also impacted by fuel requirements. These rules are found at 40 CFR Part 1033. They include several sets of standards that are being phased in. The final long-term emissions standards, referred to as Tier 4, apply to newly-built locomotive and marine diesel engines. These standards are based on the application of high-efficiency catalytic aftertreatment technology and would phased-in beginning in 2014 for marine diesel engines and 2015 for locomotives. These standards are enabled by the availability of ultra-low sulfur diesel fuel with sulfur content capped at 15 parts per million, which will be available by 2012. These marine Tier 4 engine standards apply only to commercial marine diesel engines above 600 kW (800 hp).

Labeling Diesel Fuel Pumps. Federal regulations require the labeling of diesel fuel pumps to specify the type of fuel dispensed by each pump (except in California where all diesel fuel must be ULSD). Similar vehicle instrument panel and fuel inlet/fill cap labeling is mandated for 2007 and later model year highway engines and vehicles that require ULSD fuel.* Consumers are advised to check the pump and vehicle labels to ensure they are refueling with the proper diesel fuel consistent with their vehicle warranties. For regulatory details, see 40 CFR 80.572(a).

The Energy Independence and Security Act of 2007 requires the Federal Trade Commission (FTC) to set labeling requirements that address the blending of biodiesel and other types of biomass-based diesel fuels into diesel fuel. Biodiesel is a diesel fuel produced by transforming animal fat or vegetable oil into automotive fuel. The labeling requirements became effective on December 16, 2008. The purpose of the labeling is to inform "consumers of the percent of biomass-based diesel or biodiesel that is contained in the biomass-based diesel blend or biodiesel blend that is offered for sale, as determined by the FTC." Three categories of biodiesel blends or biomass-based diesel blends are addressed:

No Label Required:

  • Fuel blends containing no more than five percent biodiesel and no more than 5 percent biomass-based diesel and that meet ASTM D975.

Labels Required:

  • Fuel blends containing more than five but no more than 20 percent biodiesel or biomass-based diesel.
  • Fuel blends containing more than 20 percent biodiesel or biomass-based diesel.

For more information on biodiesel labeling specifications, see the National Biodiesel Board Issue Brief on Biodiesel Pump Labeling.

Used Oil Prohibition in Diesel Fuel. Federal law (40 CFR 80.522) prohibits anyone from adding used motor oil, or used motor oil blended with diesel fuel, into the fuel system of model year 2007 or later diesel motor vehicles or model year 2011 or later nonroad diesel engines (not including locomotive or marine diesel engines), unless both of the following requirements have been met:

  • The vehicle or engine manufacturer has received a Certificate of Conformity under 40 CFR part 86, 40 CFR part 89, or 40 CFR part 1039 and the certification of the vehicle or engine configuration is explicitly based on emissions data with the addition of motor oil; and
  • The oil is added in a manner and rate consistent with the conditions of the Certificate of Conformity.

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