Attorney General Bonta and the California Air Resources Board Announce $372 Million Settlement With Engine Manufacturer Cummins, Inc.

Wednesday, January 10, 2024
Contact: (916) 210-6000,

OAKLAND – California Attorney General Rob Bonta and the California Air Resources Board (CARB) today announced a settlement with engine manufacturer Cummins, Inc. of Indiana (Cummins) for using illegal defeat devices to bypass vehicle emissions control equipment in diesel engines. The settlement, which is subject to court approval, includes approximately $164 million in penalties paid to CARB and $33 million to the California Attorney General’s office for the company’s environmental violations and unfair business practices; and a payment of about $175 million to CARB for mitigation programs to reduce excess nitrogen oxide (NOx) emissions caused by vehicles with Cummins engines. In an additional settlement agreement with the U.S. government, Cummins will pay a $1.642 billion federal penalty to the U.S. Environmental Protection Agency (U.S. EPA), the largest ever for a Clean Air Act case. The state’s share of both settlements is over $372 million.  

“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.”   

“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.” 

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

The Attorney General, in his independent capacity, filed a complaint, which alleged that Cummins violated state laws including California’s Unfair Competition Law and public nuisance claims. The complaint contained extensive evidence demonstrating that the defendants intentionally cheated the marketplace and consumers, and bypassed emissions tests, increasing emissions that harmfully impacted Californians’ health and safety. 

A device that alters the operation of the emissions control system - known as an ‘auxiliary emission control device’ - is permitted only under certain, specific conditions. 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 was a “defeat device” that changed the engine’s performance to meet rigorous emission standards during certification testing in the lab but made the emission control equipment less effective during real-world driving. Using defeat devices results in excess NOx emissions from the vehicles.

The Cummins engines involved in the case emitted smog-forming NOx in excess of 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.

Copies of the consent decrees are available here and here

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