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EPA Emphasizes Enforcement of Vehicle and Engine Emissions Tampering Violations


Two recent United States Environmental Protection Agency (“EPA”) actions demonstrate a renewed emphasis on prevention of conduct that circumvents vehicle emissions controls designed to limit air pollution. On November 23, 2020, the EPA Region 7 office, which serves Iowa, Kansas, Missouri, Nebraska, and nine tribal nations, announced that it reached a settlement with two Iowa companies, Menzel Enterprises Iowa Inc. of West Des Moines and UpCountry Fab and Performance LLC of Clive, Iowa.[1] EPA alleged that each of these entities took actions to circumvent vehicle emissions controls in violation of the Clean Air Act (42 U.S.C. § 7401 et seq.). Each entity agreed to pay a civil fine and certify that it would not disable vehicle emissions controls in the future.

This settlement was announced on the same day that EPA’s Office of Enforcement & Compliance Assurance issued new, nationwide guidance concerning vehicle and engine tampering and aftermarket defeat devices under the Clean Air Act.[2] This guidance is the first update to enforcement policies on this subject since the 1990s. Although this new guidance is not legally binding or an enforceable regulation, EPA guidance documents act often shape regional enforcement policies and serve to identify specific conduct that EPA enforcement actions will target.

The EPA’s guidance notes that Section 203(a)(3) of the Clean Air Act prohibits tampering with vehicle emissions controls and prohibits making and selling products that have a principal effect of bypassing, defeating, or making inoperative emissions controls. Section 205 of the Clean Air Act allows for imposition of civil penalties against violators of Section 203(a)(3). This provision applies to nearly all motor vehicles in operation – regardless of whether they are operated on-road or off-road. This includes cars, trucks, motorcycles, commercial vehicles, all-terrain vehicles, marine engines, agricultural equipment, and construction equipment.

Because modern engines and vehicles often contain multiple features and components that control emissions, both hardware and software changes to vehicles can constitute illegal tampering in violation of the Clean Air Act. First, modification or replacement of electronic control units (“ECUs”), which are computers that direct engine operation and emissions control systems, may constitute illegal tampering. Second, systems in vehicle exhaust systems, such as catalytic converters and other exhaust filtration systems, directly control emissions; replacement and modification of these vehicle parts may also constitute illegal tampering. Third, installation of “defeat devices” – equipment that bypasses the vehicle’s emissions controls in its onboard diagnostic system (“OBD system”) constitutes illegal tampering. 

The new EPA guidance emphasizes enforcement in three areas: 1) companies that manufacture or sell aftermarket components and devices that circumvent emissions controls; 2) companies with commercial vehicle fleets; and 3) vehicle service shops that tamper with vehicle emissions controls.


The recent action in Region 7 against entities allegedly installing and manufacturing devices that circumvent emissions controls, combined with the Office of Enforcement and Compliance Assurance’s new guidance, should serve as a strong reminder to all companies that have commercial vehicle fleets, and companies that manufacture, sell, and install aftermarket vehicle parts of their obligation not to alter emissions control devices or to install equipment that circumvents vehicle emissions control systems. EPA’s updated guidance on this topic may lead to increased enforcement efforts in Region 7 and nationwide, and civil penalties for illegal tampering can be significant: up to $48,192 per violation for manufacturers and dealers, and up to $4,819 per violation for individuals.




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