WASHINGTON – Caterpillar Inc. has agreed to pay a $2.55 million civil penalty to settle alleged Clean Air Act violations for shipping more than 590,000 highway and non-road engines without the correct emissions controls, the Justice Department and Environmental Protection Agency (EPA) announced today. Caterpillar also allegedly failed to comply with emission control reporting and engine-labeling requirements. Engines operating without proper emissions controls can emit excess nitrogen oxides (NOx), particulate matter and other air pollutants that impact people’s health, potentially causing respiratory illnesses and aggravating asthma.