Cummins, which makes diesel engines for trucks, among other products, will pay a record Clean Air Act civil penalty of $1.675 billion in a lawsuit brought by the US Department of Justice, the Environmental Protection Agency, and the California Air Resources Board.

Like Volkswagen before it, Cummins was found to have fitted engines—in this case, diesel engines installed in more than 630,000 Ram 2500 and Ram 3500 pickup trucks built between 2013–2019—with illegal “defeat device” software that allowed the truck engines to pass emissions tests but then emit much more pollution while in operation. The DOJ said it also found undisclosed emissions software on an additional 330,000 trucks built between 2019 and 2023.

Cummins must recall and repair the non-compliant engine software, extend the warranty period for some parts of those powertrains, fund and develop ways to reduce nitrogen oxides (NOx) from engine emissions, and implement procedures to prevent cheating in the future.

“The Justice Department is committed to vigorously enforcing environmental laws that protect the American people from harmful pollutants,” said US Attorney General Merrick 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 will pay the EPA $1.48 billion, together with $164 million to CARB and an additional $33 million to the California Attorney General’s office. An additional $175 million will be paid to CARB to fund clean-up and mitigation programs to reduce excess NOx emitted by these engines.

“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.”

For its part, Cummins agrees to the settlement but does not admit guilt. “The company has cooperated fully with the relevant regulators, already addressed many of the issues involved, and looks forward to obtaining certainty as it concludes this lengthy matter. Cummins conducted an extensive internal review and worked collaboratively with the regulators for more than four years. The company has seen no evidence that anyone acted in bad faith and does not admit wrongdoing,” Cummins said in a statement.