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U.S. EPA settles with three California auto parts companies over Clean Air Act violations

Nearly one million in penalties paid

Contact Information: 
Margot Perez-Sullivan (

For Immediate Release:

March 7, 2019

SAN FRANCISCO – Today, the U.S. Environmental Protection Agency (EPA) announced settlements with three automotive parts manufacturers, headquartered in California, for violations of the Clean Air Act. The companies allegedly manufactured or sold aftermarket auto parts that bypass or disable required emissions control systems, otherwise known as defeat devices. The three companies will pay more than $890,000 in penalties.

“One of my top priorities at EPA is preventing manufacturers from selling devices that circumvent emissions controls on cars and trucks,” said EPA Pacific Southwest Regional Administrator Mike Stoker. “We will continue to investigate and bring companies into compliance. These important actions will help reduce pollution and protect public health, particularly in parts of the Pacific Southwest that struggle with poor air quality.” 

Cars and trucks manufactured today emit far less pollution than older vehicles. This occurs through careful engine calibrations and emissions controls in exhaust systems such as catalytic converters and diesel oxidation catalysts. Aftermarket defeat devices bypass these controls and cause higher emissions. EPA testing has shown that these devices can increase vehicle emissions substantially.

Today’s announcement highlights three separate administrative settlement agreements:

Car Sound Exhaust System, Inc., dba as MagnaFlow manufactured and sold 5,674 aftermarket exhaust systems intended for model years 2001-2007 diesel trucks that enabled removal of diesel oxidation catalysts. The company, headquartered in Oceanside, Calif., will pay a penalty of $612,849.

Flowmaster, Inc. sold 446 aftermarket exhaust system parts for motor vehicles that enabled the removal of catalytic converters on light-duty gasoline vehicles. The Nevada company, headquartered in Santa Rosa, Calif., will pay a $270,000 penalty.

Weistec Engineering, Inc. manufactured or sold 110 aftermarket exhaust components for light-duty gasoline vehicles            that enabled the removal of catalytic converters. The company also developed and sold 13 custom files which allowed for the removal of catalytic converters by disabling certain emission-related trouble codes. The company, headquartered in Anaheim, Calif., will pay a penalty of $8,500.

Pollutants such as carbon monoxide, nitrogen oxide and particulate matter create poor air quality. Children, older adults, people who are active outdoors (including outdoor workers), and people with heart or lung disease are particularly at risk for health impacts due to exposure to these pollutants.

If you suspect someone is manufacturing, selling or installing illegal defeat devices, or is tampering with emissions controls, tell the EPA by writing to

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