The Discovery Channel show Diesel Brothers and its star David “Heavy D” Sparks spent nearly a decade tangled in a Clean Air Act lawsuit that ended with $851,451 in civil penalties, a permanent injunction against tampering with diesel emissions, Sparks’s arrest by federal marshals in October 2025, and a February 2026 settlement that finally cleared the outstanding legal-fees debt. What happened to the Diesel Brothers, in short: they were sued by a Utah physicians’ nonprofit, lost at trial, lost most of their appeal, refused to pay, and got hauled into jail before settling. The permanent injunction is still in force and roughly $200,000 in civil penalties remains unpaid.
Who Sued and Why
The case was not brought by the EPA or the Justice Department. It was filed by Utah Physicians for a Healthy Environment (UPHE), a nonprofit of healthcare professionals, using the Clean Air Act’s citizen-suit provision. UPHE gave notice in July 2016 and filed in January 2017 in the U.S. District Court for the District of Utah.1Justia. Utah Physicians for a Healthy Environment v. Diesel Power Gear, LLC, No. 20-4043 No separate EPA or DOJ action was ever filed.2UPHE. Diesel – Priority Issues
The defendants were Sparks, Joshua Stuart, Keaton Hoskins, and their companies Diesel Power Gear LLC and B&W Auto LLC. UPHE accused them of stripping federally required emission controls, such as diesel particulate filters and exhaust gas recirculation systems, from at least 17 vehicles, and of selling aftermarket “defeat devices” online through DieselSellerz.com.3GovInfo. Utah Physicians for a Healthy Environment v. DieselSellerz.com, Complaint Hoskins settled and was dismissed from the case, paying $83,000 in civil penalties and $85,000 toward UPHE’s legal fees.2UPHE. Diesel – Priority Issues
The $851,451 Judgment and Injunction
After a three-day bench trial in November 2019, Judge Robert Shelby issued a 58-page opinion finding the defendants liable for hundreds of Clean Air Act and Utah state violations. He called the conduct willful and imposed $851,451 in civil penalties: $761,451 to the federal government and $90,000 to Davis County, Utah.4Green Car Reports. Truck Modifiers Behind Diesel Brothers Hit With $850,000 Fine for Pollution
He also entered a permanent injunction barring the defendants from removing or disabling emission-control systems, installing or selling defeat parts, and owning or operating vehicles with disabled controls. Future violations, he warned, could trigger contempt proceedings.5Fox 13 Now. Diesel Bros Fined $850,000, Banned From Defeating Vehicle Emission Controls In January 2021 the court ordered the defendants to pay $928,602.23 in attorney fees and litigation costs on top of the penalties.2UPHE. Diesel – Priority Issues
Appeal and Reduced Penalties
The defendants appealed to the Tenth Circuit, which ruled on December 28, 2021. The appellate court largely affirmed, calling the conduct “flagrant misconduct,” but found UPHE lacked standing to pursue penalties for certain out-of-state transactions that did not affect Utah’s Wasatch Front air quality. It sent the case back for the district court to recalculate.6The Salt Lake Tribune. Appeals Court Affirms Diesel Brothers Violated Clean Air Act
On remand the penalties dropped by a combined $225,000. B&W Auto’s tampering fine fell $25,000 to $113,700, and Diesel Power Gear’s defeat-part marketing fine fell nearly $200,000 to $27,546.7Bloomberg Law. Diesel Brothers Win Penalty Reduction in Emissions Cheat Case UPHE was awarded an additional $90,535 in legal costs for defending the appeal.2UPHE. Diesel – Priority Issues
David Sparks’s Arrest
Sparks never paid. According to UPHE and court filings, he did not make a single payment toward the nonprofit’s legal fees.8The Salt Lake Tribune. After Diesel Brothers Star David Sparks’s Arrest, Settlement Talks Begin The defendants were first found in contempt of the 2021 payment order on June 24, 2024.9ABC4. Diesel Brothers Star Arrested Over Contempt, Pollution Fines
A second contempt finding came on August 4, 2025, after Sparks held a liquidation sale at Sparks Motors headquarters in July. The court treated it as an unauthorized transfer of property that violated an enforcement order.10USA Today. Diesel Brothers Star David Sparks Arrested in Lawsuit On October 2, 2025, Judge Shelby ruled Sparks had “repeatedly and willfully violated this court’s orders” and signed a bench warrant. Federal marshals arrested him the morning of October 7, 2025, and booked him into the Salt Lake County Jail.11KSL TV. David Sparks Arrested
Sparks was released two days later after a contempt hearing at which he agreed to turn over specific financial disclosures within 10 days: loan records, mortgage statements, property titles, and a sworn statement of assets. The alternative purge condition was paying the full $843,602.23 in fees.12The Independent. David Sparks Arrest – Diesel Brothers13CourtListener. Utah Physicians for a Healthy Environment v. DieselSellerz.com, Docket
His attorney, Cole Cannon, said “no crime was charged or alleged” and called the arrest “a grave injustice to the Sparks family.” In a YouTube video posted in August 2025, before the arrest, Sparks called the situation “an absolute nightmare” and said, “we made some mistakes in the early days of our business by deleting trucks and having smoky trucks and stuff like that. And that’s stuff that I’m not proud of.”12The Independent. David Sparks Arrest – Diesel Brothers
Where the Case Stands Now
At an October 24, 2025 hearing, Judge Shelby declined to lift the contempt finding but stayed contempt issues so the parties could negotiate.8The Salt Lake Tribune. After Diesel Brothers Star David Sparks’s Arrest, Settlement Talks Begin According to UPHE, Sparks and his defendant companies reached a settlement in February 2026 and paid the outstanding fees and costs debt in full.2UPHE. Diesel – Priority Issues
The settlement did not wipe the slate. The permanent injunction is still in effect, so the defendants remain barred from removing or disabling emission controls, installing or selling defeat parts, and owning or operating vehicles with disabled systems. Roughly $200,000 in civil penalties is still owed by Sparks and his companies as of early 2026.2UPHE. Diesel – Priority Issues The court docket shows the case remains active for post-judgment enforcement, with filings continuing into April 2026,13CourtListener. Utah Physicians for a Healthy Environment v. DieselSellerz.com, Docket and the DieselSellerz.com website continues to operate as a diesel truck marketplace.14DieselSellerz. DieselSellerz – Diesel Truck Marketplace