SACRAMENTO – Attorney General Rob Bonta and the California Air Resources Board (CARB) today announced a settlement with engine manufacturer Cummins, Inc. of Indiana for using illegal defeat devices to bypass vehicle emissions control equipment in diesel vehicles. The state will receive $164 million in penalties and more than $175 million for mitigation, and the company has agreed to correct the affected engines at no cost to vehicle owners.

The case involves approximately 97,000 engines in California and nearly 1 million vehicles nationwide. CARB discovered the defeat device violations in model years 2013 to 2018 Ram 2500 and 3500 trucks with the 6.7-liter diesel engine manufactured by Cummins through advanced testing methods and protocols developed to detect defeat devices – software programs that alter or shut down a vehicle’s emissions control system under normal driving operation – in the wake of the 2015 Volkswagen diesel case. The U.S. Environmental Protection Agency (U.S. EPA) partnered on the investigation, which revealed additional violations in 2019 to 2023 model year Ram 2500 and 3500 trucks.

“Cummins knowingly harmed people’s health and our environment when they skirted state emissions tests and requirements,” said Attorney General 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 happy to contribute to this landmark case.” 

“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 installed illegal defeat devices on more than 600,000 RAM pickup trucks, which exposed overburdened communities across America to harmful air pollution,” said Assistant Administrator David M. Uhlmann of 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.” 

Using defeat devices results in excess emissions from the vehicle. Only under certain, specific conditions is the software that alters the operation of the emissions control system (known as an ‘auxiliary emission control device’) permitted, typically to protect the engine. However, it must be disclosed to regulators as part of the engine’s certification. In this case, Cummins did not disclose the existence of the auxiliary emission control devices. In addition, the Cummins software changed the engine’s performance to meet rigorous emission standards during certification testing in the lab but shut down the emission control equipment during real-world driving.

The Cummins engines involved in the case emitted smog-forming oxides of nitrogen (NOx) that were above the legal limit. This pollution contributes to the formation of ozone and particulate matter and can aggravate health problems such as asthma and cardio-pulmonary disease. More than 10 million Californians live in areas with poor air quality, which aggravates health problems such as asthma and cardio-pulmonary disease and leads to significant public healthcare costs.

The settlement resolves two cases: one nationwide and one specific to California. The total settlement is more than $2 billion and includes a $1.675 billion federal penalty, the largest ever for a Clean Air Act case. California receives approximately $164 million from the consent decree in the nationwide case.

The partial consent decree of the California case pays the state about $175 million dollars for mitigation in addition to $33 million to the California Attorney General for the company’s environmental violations and for unfair business practices. The state’s share of both consent decrees is over $372 million dollars.

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