A U.S. Environmental Protection Agency (EPA) investigation into diesel truck emissions control tampering lead to a major fine for a heavy-duty parts supplier and an associated Michigan man.

Officials announced on March 20, 2025, that Kyle Offringa, 34, of Caledonia, Michigan, and Highway and Heavy Parts, LLC (HHP), a heavy-duty diesel parts supplier headquartered in Coleman, Michigan, have been sentenced and fined a total of $125,000 after reaching a plea deal on charges of conspiracy to violate the Clean Air Act (CAA).

Offringa and HHP admitted to tampering with or “tuning” emissions control systems on “numerous diesel vehicles” between at least June 2017 and March 2019. DAIM Logistics, Inc. and Patrick Oare of Fultonville, New York were named as co-conspirators in the scheme.

“Pursuant to the CAA, the EPA enacted regulations that required heavy-duty diesel engine manufacturers to limit emissions on those engines. To comply with these regulations, manufacturers install hardware components, including filters, exhaust recirculation systems, and exhaust aftertreatment systems. Heavy-duty diesel trucks are also required under the CAA to maintain an onboard-diagnostic system (“OBD”), which monitors the functionality of the hardware emissions control components. If the OBD detects that an emissions control component is not working, or has been removed, it will ultimately put the truck into what is known as “limp mode,” which limits the top speed to as low as 5 miles per hour.  This is designed to incentivize truck operators to repair any faulty components,” officials explained.

“As part of the conspiracy, HHP referred its customers who had removed emissions hardware on their heavy-duty diesel trucks to Offringa, who then reprogrammed the OBDs to bypass the CAA monitoring functions so the trucks would remain operational in exchange for a fee of $1,000 to $1,500 per OBD.  HHP charged its customers approximately $250 for each tune performed by Offringa on top of what Offringa charged,” the U.S. Attorney’s Office for the Northern District of New York continued.

The case was investigated by the EPA’s Criminal Investigations Division.