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

In January 2021, the US Department of Justice announced that Cummins Inc. was facing a record-breaking penalty of more than $2 billion for accusations of cheating on US engine emissions tests. Cummins, a US-based diesel engine manufacturer, was accused of having installed “defeat devices” on its diesel engines in order to manipulate tests for nitrogen oxide (NOx) emissions. The penalty involves both a criminal penalty of $400 million and a civil penalty of more than $1.5 billion, and is the largest ever penalty imposed for Clean Air Act violations. The settlement also requires Cummins to implement major changes in its engine product development and emissions defeat-device detection-prevention practices, and to install more than $1 billion in emissions control technologies on its engines.