Tenth Circuit Decision Reinforces Federal Clean Air Act Citizen Suits Against Mobile Sources

February 2022

Environmental, Energy, & Climate Change Law and Regulation Reporter, Volume 2, Number 5

In its recent decision in Utah Physicians for a Healthy Environment (UPHE) v. Diesel Power Gear, LLC, et al., a matter involving the hosts of Discovery Channel’s popular show “Diesel Brothers,” the Tenth Circuit unanimously upheld for the first time a successful citizen suit under the Clean Air Act (“CAA”) targeting mobile source emissions. While typically citizen suits under the CAA have only been successful against stationary sources, in UPHE the Tenth Circuit found that citizens and citizen groups could effectively demonstrate Article III standing to challenge mobile sources’ violations of the CAA.


In 2017, Utah Physicians for a Healthy Environment (“UPHE”), a nonprofit organization of Utah healthcare professionals and concerned citizens, filed suit in the United States District Court for the District of Utah against a group of Utah companies and individuals involved with the Discovery Channel show “Diesel Brothers.” The “Diesel Brothers” Defendants bought and made custom modifications to large diesel trucks for resale and eventually featured these custom built trucks on its Discovery Channel show. UPHE claimed that the defendants violated the CAA and Utah’s State Implementation Plan by tampering with emissions-control devices and installing “defeat devices” on various vehicles that would allow the vehicles to evade emissions standards. UPHE further alleged these violations resulted in “the excessive emission of harmful pollutants from diesel vehicles” into the air shed of the Wasatch Front, an area in northern Utah with some of the most polluted air in the country.

The U.S. District Court for the District of Utah found in favor of UPHE, ordering the defendants to pay over $760,000 in civil penalties and granting injunctive relief enjoining the defendants from installing defeat devices and owning or selling any vehicles with inoperable emissions control systems.

You can read the full article online here or download and view a PDF of the article here.