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New Clean Diesel Rule Major Step in a Decade of Progress

Release Date: 05/11/2004
Contact Information:

Contact: Cynthia Bergman, 202-564-9828 /
John Millett, 202-564-7842 /

(05/11/04) The Bush Administration’s Clean Air Nonroad Diesel Rule, signed today, will cut emission levels from construction, agricultural and industrial diesel-powered equipment by more than 90 percent. The new rule will also remove 99 percent of the sulfur in diesel fuel by 2010, resulting in dramatic reductions in soot from all diesel engines.

“We are going to make that burst of black smoke that erupts from diesels a thing of the past,” EPA Administrator Mike Leavitt said. “We’re able to accomplish this in large part because of a masterful collaboration with engine and equipment manufacturers, the oil industry, state officials, and the public health and environmental communities.”

When the full inventory of older nonroad engines has been replaced, the nonroad diesel program will annually prevent up to 12,000 premature deaths, one million lost work days, 15,000 heart attacks and 6,000 children's asthma-related emergency room visits. The anticipated costs vary with the size and complexity of the equipment but are in the range of one to three percent of the total purchase price for most equipment categories. While the estimated added cost for low-sulfur fuel is about seven cents per gallon, the net cost is projected to average about four cents per gallon because the use of ultra-low sulfur fuel could significantly reduce engine maintenance expenses. The overall benefits of the nonroad diesel program are estimated to significantly outweigh the costs by a ratio of 40 to1.

The Clean Air Nonroad Diesel Rule is the latest round in EPA’s decade-long effort to make diesel engines and fuels cleaner. This new rule complements the Clean Diesel Truck and Bus Rule (announced December 21, 2000), which will put the cleanest running heavy-duty trucks and buses in history on America’s roads, building a fleet that will be 95 percent cleaner than today’s trucks and buses. On-highway compliance requirements take effect with the 2007 model year.

Today, EPA also took the first step toward proposing new emission standards for diesel engines used in locomotives and marine vessels by issuing an advance notice of proposed rulemaking. Standards being considered would apply to new marine diesels and both new and existing diesel locomotives. Without new standards, the Agency projects that railroad and marine diesels will cause some 27 and 45 percent respectively of total nitrogen oxides (NOx) and particulate matter (PM) pollution coming from mobile sources.

The Agency’s Clean Diesel Program accentuates the benefit of these historic rulemakings through a suite of voluntary programs that focus on vehicles and equipment in use today. These include the Clean School Bus USA Program, the Voluntary Diesel Retrofit Program and SmartWay Transport Partnership.

The Clean Air Nonroad Diesel Rule announced today will result in the widespread introduction of emission control systems, a move comparable to the advent of catalytic converters for cars in the 1970s. The new standards, to be phased in over the next several years, will result in reductions of pollution equivalent to having some two million fewer trucks on the road. The nonroad rule represents an unprecedented commitment and collaboration that included the White House, EPA, the Office of Management and Budget, the environmental community, states and local governments, engine and equipment manufacturers, refiners, technology companies, and other groups and associations.

Standards for new engines will be phased in starting with the smallest engines in 2008 until all but the very largest diesel engines meet both NOx and PM standards in 2014. Some of the largest engines, 750+ horsepower, will have one additional year to meet the emissions standards.

Diesel fuel currently contains about 3,000 parts per million (ppm) sulfur. The new rule will cut that to 500 ppm in 2007 and 15 ppm by 2010.

These clean diesel programs are part of the suite of clean air actions that will dramatically improve air quality. The Clean Air Rules of 2004 provide national tools to achieve significant improvement in air quality and the associated benefits of improved health, longevity and quality of life for all Americans.

More information on EPA’s clean diesel programs, including the Clean Air Nonroad Diesel Rule, is available at: Information about the Clean Air Rules of 2004 is available at: