A Pennsylvania mechanic and the trucking company he worked for were sentenced for conspiracy and violations of the Clean Air Act for tampering with emissions control systems on at least eight vehicles.

Diesel mechanic Leon Martin, 42, was sentenced to two years of probation, with three months of home curfew, and a $500,000 fine, according to the U.S. Attorney’s Office for the Middle District of Pennsylvania.

Frock Brothers Trucking, Inc. of New Oxford, Pennsylvania, was sentenced to two years of probation and an $80,000 fine.

In September 2024, Frock Brothers Trucking pleaded guilty to one count of violating the Clean Air Act while Martin pleaded guilty to one count of felony violation of the Clean Air Act and a second count of felony conspiracy.

Officials say that while working as a mechanic for Frock Brothers, Martin provided “tuning” or “reprogramming” services in which he tuned the engine control modules (ECMs) on diesel trucks from 2018 through October 2023.

“In November and December 2018, Martin did work for Frock Brothers Trucking, Inc., a long-distance trucking company that delivers general freight and other products.  At that time, Martin, Frock Brothers, and others, conspired to tamper with the emission control hardware on approximately eight diesel vehicles of Frock Brothers, in violation of the Clean Air Act. The illegal actions were for the purpose of obtaining economic benefits, including, among other things, reduced or avoidance of repair costs, fuel savings from improved fuel economy on modified vehicles, and reduced expenditures on diesel exhaust fluids required to operate emissions systems components. As part of the scheme, Frock Brothers removed the vehicles’ ECMs from their engines and shipped them to Leon Martin for reprogramming. Once the devices were “tuned,” Martin shipped them back to Frock Brothers, where they were reinstalled on the trucks,” officials said.

The case was investigated by the Environmental Protection Agency’s Criminal Investigations Division (EPA-CID).

“Tampering with required emissions monitoring devices in heavy duty vehicles results in a significant increase in air pollution,” said Allison Landsman, EPA-CID Special Agent in Charge. “Today’s sentencing demonstrates that we will hold violators accountable for breaking our environmental laws.”