The $2 billion settlement that the Department of Justice and Environmental Protection Agency finalized with diesel engine-maker Cummins on Wednesday serves as a cautionary tale for all companies after years of lax enforcement of the Clean Air Act.

Regulators alleged Cummins installed emissions-control-defeat devices on diesel engines it supplied for more than 600,000 Ram pickup trucks over the course of a decade. Under the consent agreement, which concludes a regulatory review that began four years ago, Cummins did not admit wrongdoing.