Diesel Brothers $4.4 Million Lawsuit: Ruling, Appeal, and Arrest

The Diesel Brothers lawsuit was a nine-year Clean Air Act citizen suit brought in 2017 by Utah Physicians for a Healthy Environment against David “Heavy D” Sparks and his companies for stripping federally required pollution controls from diesel pickup trucks and selling defeat devices. It ended in a February 2026 settlement, but not before the court imposed $851,451 in civil penalties, ordered nearly $1 million in attorney fee reimbursement, entered a permanent injunction against further tampering, and, in October 2025, jailed Sparks for two nights on a contempt-of-court warrant.

Who Sued and Why

Utah Physicians for a Healthy Environment (UPHE), a nonprofit founded in 2007 by healthcare professionals pushing for cleaner air in Utah, filed the suit on January 10, 2017, in the U.S. District Court for the District of Utah. The named defendants were Diesel Power Gear LLC (DPG), B&W Auto LLC, Sparks Motors LLC, and four individuals: David W. Sparks, David Kiley, Joshua Stuart, and Keaton Hoskins. Sparks was CEO and owner of both DPG and B&W Auto. Stuart was DPG’s part-owner, CFO, and COO. Hoskins worked on the trucks and handled marketing.¹

The Clean Air Act lets private citizens bring enforcement suits when the government has not acted. UPHE’s attorneys initially calculated a theoretical maximum penalty of $4.4 million based on the scope of the violations, which involved roughly 20 modified trucks and nationwide defeat-parts sales.²

What the Trucks Actually Did

The Discovery Channel show Diesel Brothers followed Sparks, Kiley, and their crew building custom diesel pickups. The legal trouble came from what happened to those pickups’ emissions equipment during the builds. The court found that B&W Auto stripped pollution controls from trucks and replaced them with equipment designed to defeat federal emissions standards. The hardware included straight pipes, delete pipes, vertical exhaust stacks, EGR delete kits, and software “delete tunes” that reprogrammed onboard diagnostic systems to suppress warning lights.¹

The modifications removed diesel particulate filters, oxidation catalysts, exhaust gas recirculation systems, selective catalytic reduction systems, and NOx sensors. UPHE purchased one of the modified trucks and had it independently tested. It emitted nitrogen oxides at 36 times the rate of a stock truck and particulate matter at 21 times the stock rate.³ Videos of the trucks “rolling coal,” billowing plumes of black smoke, came in as evidence at trial.⁴

Beyond the trucks themselves, DPG sold 164 individual defeat parts through its website, generating about $21,000 in revenue. The company also made roughly $50,000 in profit per sweepstakes truck it gave away through promotions.¹

How the Court Ruled

A four-day bench trial took place in November 2019, and Judge Robert Shelby issued his trial order in March 2020. The liability findings were spread across the defendants:

B&W Auto LLC was liable for tampering with pollution controls, installing defeat parts, marketing defeat parts as components of vehicles sold, and violating Utah’s state implementation plan.
Diesel Power Gear LLC was liable for 88 defeat part marketing violations through its website.
David Sparks was liable for the sale of 88 defeat parts and, as a responsible corporate officer who knew about the violations and failed to stop them, liable for B&W Auto’s tampering and defeat part violations.
Joshua Stuart was liable for 88 defeat part marketing violations as a co-owner and officer of DPG.
Keaton Hoskins was liable for tampering and defeat part violations on two trucks and for owning or operating vehicles with disabled emissions systems in violation of Utah law.

David Kiley, one of the show’s on-air figures, was dismissed from the case through a stipulated agreement.¹

The Penalty and the Appeal

UPHE had sought up to $4.4 million. The court ordered considerably less. Judge Shelby imposed a total civil penalty of $851,451, split between $761,451 payable to the federal government and $90,000 to Davis County, Utah.⁴ DPG, Sparks, and Stuart were held jointly and severally liable for a $227,218 portion of that penalty.⁵ The court also entered a permanent injunction barring the defendants from removing emissions controls, installing defeat devices, selling defeat parts, or owning vehicles with disabled emissions systems.³

DPG, B&W Auto, Sparks, and Stuart appealed. On December 28, 2021, the U.S. Court of Appeals for the Tenth Circuit affirmed the liability findings in large part but narrowed the penalties. The appellate court held that UPHE lacked standing to seek penalties for violations that did not contribute to air pollution along Utah’s Wasatch Front, meaning out-of-state defeat device sales could not be penalized. The court described the defendants’ conduct as “flagrant misconduct” while remanding for a recalculation.⁵ The practical effect was a reduction in civil penalties of roughly $200,000, with the trial court later cutting another $25,000.³

Attorney fees added a second financial layer. In January 2021, Judge Shelby ordered the defendants to reimburse UPHE $928,602.23 in legal costs, and in July 2022 the district court added another $90,535 for appellate work.³

Nonpayment, Contempt, and Sparks’s Arrest

Sparks did not pay. According to the Salt Lake Tribune, as of October 2025 he had not paid any of the required funds to the nonprofit, citing an inability to track financial documentation.⁶ The nonpayment triggered a series of enforcement actions. A federal judge issued an initial contempt order in June 2024. In January 2025, the court issued an enforcement order barring Sparks from moving any personal property without court authorization.⁷ That summer, Sparks held a garage sale at the Sparks Motors headquarters that violated the January order. A judge initially ordered the sale postponed, and the allocation of proceeds became a point of contention.⁸

On October 2, 2025, Judge Shelby formally held Sparks in contempt for failing to pay the court-ordered fees and for repeatedly violating court orders. Five days later, on October 7, a U.S. Marshal arrested Sparks in Salt Lake City on a federal bench warrant.⁹ He spent two nights in the Salt Lake County jail before being released on October 9 after agreeing to provide missing documents the court had requested.⁶

The Social Media Response

Sparks, who has roughly 3.9 million Instagram followers and 4.47 million YouTube subscribers, took to social media with his side of the story.⁸ On October 15, he released a 30-minute YouTube video that reached 3.5 million views, naming UPHE members and calling the lawsuit “a civil dispute fueled by greed and attorneys’ fees.”⁶

UPHE filed an emergency motion alleging that Sparks’s posts triggered a “barrage of intimidating and sometimes violent emails and messages” directed at the nonprofit’s staff, board, attorneys, and their families. The group asked the court to order Sparks to remove the posts and stop encouraging his followers to confront them. Judge Shelby declined, finding that the social media activity did not meet the legal threshold for an injunction or restraining order.⁶

How the Case Ended

At an October 24, 2025 hearing, Judge Shelby declined to lift the contempt finding but stayed contempt-related issues so the parties could focus on settlement.⁶ Sparks’s contempt was later purged once he turned over the agreed-upon documents.³

By February 2026, the parties reached a settlement. Sparks and his companies paid their full legal fees and costs debt to UPHE. They remain liable for approximately $200,000 in unpaid civil penalties owed to the federal government, and they remain bound by the permanent injunction prohibiting any tampering with diesel truck emissions systems.³

1
GovInfo. Utah Physicians for a Healthy Environment v. Diesel Power Gear LLC, 2:17-cv-00032-RJS-DBP
2
UPHE. Update on Diesel Bro Lawsuit
3
UPHE. Diesel
4
Green Car Reports. Truck Modifiers Behind Diesel Brothers Hit With $850,000 Fine for Pollution
5
United States Court of Appeals for the Tenth Circuit. Utah Physicians for a Healthy Environment v. Diesel Power Gear LLC, No. 20-4043
6
Salt Lake Tribune. After Diesel Brothers Star David Sparks Jailed, Settlement Talks Underway
7
USA Today. Diesel Brothers Star David Sparks Arrested in Connection With Lawsuit
8
The Drive. Diesel Brothers Influencer Heavy D Arrested for Failure to Pay $850K in Environmental Lawsuit Fees
9
People. Diesel Brothers Star Arrested in Connection With Environmental Lawsuit