Diesel-engine maker Cummins Inc. agrees to pay $1.675B in emissions-testing cheat scheme

WASHINGTON – The Justice Department, Environmental Protection Agency (EPA), California Air Resources Board (CARB) and the California Attorney General’s office today [Jan. 10, 2023] released the details of a proposed settlement with diesel engine maker Cummins Inc. for alleged violations of the Clean Air Act and California law. Beyond agreeing to pay a $1.675 billion civil penalty – the largest ever assessed in a Clean Air Act case – Cummins has agreed to spend more than $325 million to remedy the violations, which included the use of software “defeat devices” that circumvented emissions testing and certification requirements.

Under the settlement, Cummins must complete a nationwide vehicle recall to repair and replace the engine control software in hundreds of thousands of RAM 2500 and RAM 3500 pickup trucks equipped with the company’s diesel engines. Cummins will also extend the warranty period for certain parts in the repaired vehicles, fund and perform projects to mitigate excess ozone-creating nitrogen oxides (NOx) emitted from the vehicles and employ new internal procedures designed to prevent future emissions cheating. In total, the settlement is valued at more than $2 billion.

NOx pollution contributes to the formation of harmful smog and fine particulate matter in air.  Children, older adults, people who are active outdoors, and people with heart or lung diseases are particularly at risk for health effects related to smog or particulate matter exposure. Nitrogen dioxide formed by NOx emissions can aggravate respiratory diseases, particularly asthma, and may also contribute to asthma development in children.

“Today’s landmark settlement is another example of the Biden-Harris administration working to ensure communities across the United States, especially those that have long been overburdened by pollution, are breathing cleaner air,” said EPA Administrator Michael Regan. “Today we’ve reaffirmed that EPA’s enforcement program will hold companies accountable for cheating to evade laws that protect public health.”

“The Justice Department is committed to vigorously enforcing environmental laws that protect the American people from harmful pollutants,” said Attorney General Merrick B. Garland. “The types of devices we allege that Cummins installed in its engines to cheat federal environmental laws have a significant and harmful impact on people’s health and safety. This historic agreement makes clear that the Justice Department will be aggressive in its efforts to hold accountable those who seek to profit at the expense of people’s health and safety.”

“Cummins installed illegal defeat devices on more than 600,000 RAM pickup trucks, which exposed overburdened communities across America to harmful air pollution,” said David M. Uhlmann, Assistant Administrator for EPA’s Office of Enforcement and Compliance Assurance. “This record-breaking Clean Air Act penalty demonstrates that EPA is committed to holding polluters accountable and ensuring that companies pay a steep price when they break the law.”

“Today’s agreement, which includes the largest-ever Clean Air Act civil penalty, stands as notice to manufacturers that they must comply with our nation’s laws, which protect human health and the health of our environment,” said Assistant Attorney General Todd Kim of the Justice Department’s Environment and Natural Resources Division. “We appreciate the work of our partners, the EPA and the State of California, in helping us reach this significant settlement.”

“Cummins knowingly harmed people’s health and our environment when they skirted state emissions tests and requirements,” said California Attorney General Rob Bonta. “Today’s settlement sends a clear message: If you break the law, we will hold you accountable. I want to thank our federal and state partners for their collective work on this settlement that will safeguard public health and protect consumers across the country.”

“The collaboration between California and its federal partners makes it clear that companies will be held accountable for violating essential environmental laws that are in place to provide the clean air that communities across California and the nation want and deserve,” said CARB Executive Officer Dr. Steven Cliff. “California’s air quality regulations protect public health and are backed by a world-class emissions testing laboratory that ensures CARB’s enforcement efforts are rigorously supported with data and science, which CARB was pleased to contribute to this landmark case.”


As in prior cases against other manufacturers, EPA discovered defeat devices in Cummins engines used in RAM pickup trucks through testing at the agency’s National Vehicle and Fuel Emissions Laboratory. That testing of RAM trucks was done as follow-up on a 2015 EPA warning to manufacturers that the agency planned to conduct special testing to identify defeat devices using driving cycles and conditions that were non-standard, but still reflected normal vehicle operation and use.

The terms of the proposed settlement with Cummins are spelled out in two consent decrees that the United States and California filed today with the U.S. District Court for the District of Columbia. In a related set of complaints filed today, the United States and California allege that nearly a million model year 2013-2023 RAM 2500 and RAM 3500 pickup trucks with Cummins diesel engines utilized undisclosed engine control software features, and more than 630,000 of those trucks made in model years 2013-2019 had illegal emissions control software defeat device features. Those software defeat devices helped the trucks pass standard EPA emissions tests, but they artificially reduced the effectiveness of the emission controls – and increased NOx emissions – during normal driving outside of the standard test conditions.

Recall and Repair Program

Cummins sought all EPA and CARB emission certifications for the RAM trucks equipped with its engines, even though the trucks were sold by the RAM truck division of Fiat Chrysler and its dealers. The settlement requires Cummins to work with Fiat Chrysler and its dealers on a vehicle recall and repair program that will remove all defeat devices from the affected 2013-2019 RAM trucks free of charge and bring the vehicles into compliance with applicable emissions standards under the Clean Air Act. The repair only involves software updates. Cummins has already started the recall and repair program required by the settlement.

Cummins must repair at least 85% of the 2013-2019 RAM trucks equipped with defeat devices within three years. The company must offer a special extended warranty covering emission control system parts on 2013-2019 RAM trucks that receive the replacement software. Cummins also must test some of the repaired trucks over a number of years to ensure that the trucks continue to meet emissions standards over time.

Mitigation Programs

As another requirement of the settlement, Cummins must fully offset the excess NOx emissions from the 2013-2019 RAM trucks that were equipped with defeat devices. For California, Cummins will make a lump sum payment to CARB of slightly more than $175 million to fund mitigation actions or projects that reduce NOx emissions in California through CARB mitigation programs. For the rest of the country, Cummins will secure offsetting NOx reductions by working with railroad locomotive owners on two types of locomotive emission reduction projects. First, Cummins will finance and ensure the replacement of 27 old, high-emitting diesel locomotive engines with new, low-emitting diesel or electric engines. Second, Cummins will fund and complete 50 projects that will reduce idling time for diesel-powered switch locomotives to reduce fuel usage and emissions of NOx, particulate matter, volatile organic compounds and carbon dioxide.

Source: “United States and California Announce Diesel Engine Manufacturer Cummins Inc. Agrees to Pay a Record $1.675 Billion Civil Penalty in Vehicle Test Cheating Settlement,” Jan. 10, 2024 Environmental Protection Agency press release.

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