Diesel Brothers Fail to Overturn Clean Air Act Violations, Cited for “Flagrant Misconduct.”

Salt Lake City, UT – In a significant victory for cleaner air and the rule of law, the 10th Circuit Court of Appeals upheld federal Chief Judge Robert Shelby’s 2019 decision that Utah Physicians for a Healthy Environment properly sued – and prevailed against – the Diesel Brothers under the Clean Air Act. 

“We are a step closer to clean, healthy air in Utah thanks to this decision,” said Dr. Brian Moench, UPHE’s president.

The decision of the Appeals Court continues the prohibition against the Diesel Brothers from defeating emission control systems in diesel vehicles, and upholds in large part the penalties assessed against the Discovery Channel actors. 

“Specifically, the court upheld Judge Shelby’s previous decision that private citizens can use the provisions of the Clean Air Act to hold the Diesel Brothers accountable for adding to our community’s pollution burden by deliberately tampering with pollution control devices on cars and trucks,” said Dr. Moench. “But the appeals court’s ruling today has broad implications. It is a victory for public health protection, for preserving the rule of law, and for the right of citizens to pursue punishment of any company that might have a similar business practice that disregards the rights of citizens to breathe clean air.”

To the Diesel Brothers’ claim that their penalties were disproportionate to their violations, the appeals ruled, “In light of the flagrant misconduct by Defendants, we see no gross disproportion.”

“The decision of the Appeals Court is welcome news,” said UPHE attorney Reed Zars. “It represents a shot across the bow to those who traffic in the illegal modification of emission controls in cars and trucks,” Zars stated. 


·      The appeals court rejected the argument of Diesel Brothers that they were protected from federal enforcement by selling their illegally-modified trucks “as-is.”  According to the appeals court:

Defendants’ argument is a nonstarter. The statute certainly does not explicitly provide an exception for as-is sales. Nor does anything in the CAA provide a rationale for such an exception. On the contrary, the as-is nature of a sale concerns only the relationship between the seller and the buyer, whereas the CAA’s concern is the relationship between the user of the vehicle and the public that must suffer from that vehicle’s emissions. 

·      The appeals court upheld the right of citizens to sue companies and individuals who, like the Diesel Brothers, harm the health of the public by tampering with emission controls on cars and trucks. 

·      The appeals court held that this right is supported by the U.S. Constitution, the federal Clean Air Act, and Utah’s air pollution regulations. 

·       According to the appeals court:  “We therefore hold that UPHE has standing to challenge Defendants’ violations that contributed to the unhealthy air in the Wasatch Front. The EPA has determined that the Salt Lake City area, which includes where Defendants conduct business, is a nonattainment area for 24-hour levels of fine particulate matter (PM2.5).12 See 40 C.F.R. § 81.345. Those who reside in that area can fairly trace injuries they suffer from the polluted air to any contributor of prohibited emissions in the area.”

·      The appeals court rejected Diesel Brothers’ argument that citizens could not enforce the prohibition against removing emission controls from vehicles.  According to the appeals court, “UPHE argues that ‘[a]n anti-tampering requirement prohibiting the removal or defeat of an emission control device, such as a catalytic converter, that is designed to reduce emissions on a continuous basis, is plainly a requirement that ensures the reduction of emissions on a continuous basis,’ and therefore satisfies the statutory definition of an emission standard or limitation. Aplee. Br. at 28–29. This argument has considerable force.”

·      The appeals court upheld Judge Shelby’s assessment of penalties in large part, only requiring a review of the penalties for those illegally modified trucks and parts that were sent out of state and did not directly pollute the air of Utah.  

·      The appeals court also rejected Diesel Brothers’ argument that the penalties they were assessed violated the U.S. Constitution.  According to the appeals court: “Finally, Defendants argue that the penalties imposed on them for violations of Utah’s SIP are “excessive and disproportionate to the gravity of the violations,” and therefore unconstitutional under the Eighth Amendment. Aplt. Br. at 47 . . .  The test for whether a fine is excessive under the Eighth Amendment is whether “it is grossly disproportional to the gravity of a defendant’s offense.” United States v. Bajakajian, 524 U.S. 321, 334 (1998). In light of the flagrant misconduct by Defendants, we see no gross disproportion.”

Click here to read more about the lawsuit.