The US Environmental Protection Agency (EPA) has reached settlements with two Iowa companies for allegedly tampering with car engines to render emissions controls inoperative, in violation of the federal Clean Air Act.

According to EPA, Menzel Enterprises Iowa Inc. of West Des Moines installed “defeat devices” in at least five vehicles. EPA also alleged that UpCountry Fab and Performance LLC of Clive, Iowa, removed emission control equipment and/or sold “defeat devices” on at least 48 occasions.

Under the terms of the settlements, each company will pay a civil penalty and must certify that it will refrain from disabling emission controls in the future.

Tampering of car engines, including installation of aftermarket defeat devices intended to bypass manufacturer emissions controls, results in significantly higher releases of nitrogen oxides and particulate matter, both of which contribute to serious public health problems in the United States. These problems include premature mortality, aggravation of respiratory and cardiovascular disease, aggravation of existing asthma, acute respiratory symptoms, chronic bronchitis, and decreased lung function. Numerous studies also link diesel exhaust to increased incidences of lung cancer.

Stopping aftermarket defeat devices for vehicles and engines is a top priority for EPA. The Agency identified this goal as one of seven National Compliance Initiatives in 2019.