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

In 2019, the U.S. Environmental Protection Agency and the Department of Justice accused the U.S. engine maker, Cummins, of cheating on emissions tests. The two entities said that the company, which supplies diesel engines to many truck and bus manufacturers, had installed a defeat device on models sold between 2007 and 2018. Under this device, Cummins’ engines would seem to perform better on tests than they actually did. The EPA and DOJ alleged that the company’s engines emitted nitrogen oxides (NOx) that were seven to eight times those allowed by law.

Cummins agreed to pay a record settlement of $1 billion — the largest penalty under the Clean Air Act ever — and implement other changes, such as using certain technologies to reduce NOx emissions and instituting new auditing and emissions standards. The company also agreed to pay an additional $83 million in civil penalties.