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Press Release

Detroit Diesel Corporation to Pay Penalty and Reduce Exposure to Harmful Diesel Exhaust to Resolve Clean Air Act Violations

For Immediate Release
Office of Public Affairs

Department of Justice and the U.S. Environmental Protection Agency (EPA) today announced a settlement with Detroit Diesel Corporation that resolves alleged violations of the Clean Air Act for selling heavy-duty diesel engines that were not certified by EPA and did not meet applicable emission standards.   Under the settlement, Detroit Diesel will spend $14.5 million on projects to reduce nitrogen oxide and other pollutants, including replacing high-polluting diesel school buses and locomotive engines with models that meet current emissions standards.  Detroit Diesel will also pay a $14 million civil penalty.

The government’s complaint, filed today along with the settlement, alleges that Detroit Diesel violated the Clean Air Act by introducing into commerce 7,786 heavy-duty diesel engines for use in trucks and buses in model year 2010 without a valid EPA-issued certificate of conformity demonstrating conformance with Clean Air Act standards to control nitrogen oxide (NOx) emissions.  The complaint also alleges that the engines did not conform to emission standards applicable to model year 2010 engines. To mitigate the harm posed by the alleged violations, the school bus and locomotive replacement projects required by the settlement will reduce ambient air levels of nitrogen oxide and other pollutants.  EPA will approve where the projects are to be performed, based on various criteria, including whether the area already does not meet Clean Air Act standards and whether the area includes low-income communities.  In addition, the school bus program will improve air quality inside school buses by reducing exposure to diesel exhaust.  Diesel exhaust poses a lung cancer hazard for humans and can cause non-cancer respiratory effects such as asthma.

“This case demonstrates the critical importance of EPA’s vehicle and engine certification program to achieving the goals of the Clean Air Act,” said Assistant Attorney General John C. Cruden for the Justice Department’s Environment and Natural Resources Division.  “By not certifying the engines in accordance with the rules, Detroit Diesel Corp. increased pollution and undercut competitors. We will uphold the integrity of that program by holding accountable those that skirt the rules.”

“Today’s settlement protects clean air for many communities and vulnerable people across the country, including school children,” said Cynthia Giles, Assistant Administrator for EPA’s Office of Enforcement and Compliance Assurance. “EPA will continue to hold engine manufacturers accountable for meeting emissions standards that protect public health and the air we breathe.”

The Clean Air Act requires manufacturers to obtain a certificate of conformity demonstrating compliance with emission standards before introducing an engine into commerce. Certificates of conformity cover only those engines produced within a single model year. A model year for an engine family of engines ends either when the last such engine is produced, or on Dec. 31 of the calendar year, for which the model year is named, whichever date is sooner.

The complaint alleges that Detroit Diesel commenced construction of the engines during model year 2009, but did not complete construction of the engines until model year 2010.  Because Detroit Diesel completed all manufacturing and assembling processes for the engines in 2010, the complaint alleges that the engines were produced in 2010 and required a certificate of conformity demonstrating compliance with 2010 emission standards.  From approximately Jan. 5, 2010, through approximately June 1, 2010, Detroit Diesel sold the engines for on-highway use in heavy duty vehicles.  Because the engines were not certified to the stringent 2010 NOx emission standards, Detroit Diesel’s introduction of these engines resulted in excess emissions.  The engines were manufactured in Detroit, Michigan, but were introduced into commerce across the country.

Under the consent decree, Detroit Diesel will be required to implement projects to replace high-polluting school buses with school buses that meet current federal emissions standards and replace or repower high-polluting switch locomotives.  Detroit Diesel is also required to post data and information about the clean diesel projects on a public website.

Detroit Diesel is a Michigan corporation that began as a diesel engine manufacturing division of the General Motors Corporation in 1938.  It is currently a wholly-owned subsidiary of Daimler Trucks North America.  Detroit Diesel manufactures heavy-duty diesel engines, axles and transmissions for the on-highway and vocational truck markets.

The consent decree was lodged in the District Court for the District of Columbia.  Notice of the lodging will appear in the Federal Register allowing for a public comment period of not less than 30 days before the consent decree can be entered by the court as final judgement.  The $14 million civil penalty is due 30 days after the effective date of the consent decree.  To view the consent decree:

More information about today’s settlement:

More information about EPA’s Clean Air Act vehicle and engine enforcement case resolutions:

Updated April 5, 2024

Press Release Number: 16-1168