U.S. engine maker facing largest Clean Air Act penalty ever over emissions test cheating accusations

In January 2020, Cummins Inc., one of the largest engine manufacturers in the United States, agreed to pay a record-breaking fine of $2.17 billion to resolve a Clean Air Act violation related to allegations of cheating on diesel emissions tests.

The Justice Department said that Cummins’ Texas-based branch had manufactured and sold more than 500,000 heavy-duty truck engines with illegal technology aimed at bypassing rules meant to reduce smog-causing nitrogen oxide emissions. These modified engine designs allegedly allowed vehicles to produce up to 14 times more smog-causing pollutants than permitted by the Clean Air Act.

Cummins was also accused of making false statements to regulatory agencies about the emissions controls on the engines. It was alleged that the company had installed “defeat” devices that could activate the emission control system during testing, but then disabled it once the testing was completed.

To cover the fine, Cummins agreed to pay $1 billion in civil penalties and also to spend $750 million on emissions control and related technologies. The company also plans to invest another $500 million in “green” projects to help reduce emissions from the transportation sector.