Isaac Allen, owner of Red Barn Diesel Performance, was sentenced May 7 to three years of probation for tampering with environmental monitoring devices on multiple diesel vehicles and obstructing the investigation of the Environmental Protection Agency.

According to a press release from the U.S. Attorney’s Office of the District of Maine, U.S. District Judge Nancy Torresen sentenced Allen to a three-year term of probation and a $40,000 fine, the maximum recommended amount for his offense level. Allen initially pled guilty to the crime in November 2024. As part of his probation, Allen is required to ensure that all vehicles owned by him and his company are in compliance with the Clean Air Act by having all required emissions controls and an on-board diagnostic system functioning within its original parameters.

Court documents state that Allen conspired with two co-conspirators, referred to as Company A and Company B, to sell electric vehicles which had illegal software, known as tunes, installed. Company A, which on multiple occasions between January 2017 and September 2020 referred their customers to Allen, sold and installed emission control defeat devices such as EGR block-off plates, services which they advertised on Facebook.

In addition, Allen purchased tunes from Company B, and would download them into the vehicle’s OBD system, making it so that it would not detect malfunctions in the emissions control components. The press release noted that, when given a Clean Air Act Request for Information from the EPA, Allen submitted a document that “materially underrepresented the number of illegal tunes he had installed.”

A 2020 report from the EPA reveals how the tampering of defeat devices on diesel vehicles is a systemic problem across the country. Maine in particular is ranked fourth in the nation, with an estimated 2,794, or 13.5% of the total number of registered diesel vehicles, having had their defeat devices tampered with. Percentage-wise, only Wyoming, Idaho and North Dakota rank higher. This has led to an estimated 2,859 tons of excess NOx emissions and 27 tons of excess PM25 emissions.

In a Department of Justice press release regarding Allen’s guilty plea, Tyler Amon, the special agent in charge of the EPA’s Criminal Investigation Division in Maine, laid out some of the environmental consequences of vehicle tampering operations such as the one Allen and his co-conspirators conducted.

“The pollution that results from excess vehicle emissions can lead to serious health conditions and has been linked to increased respiratory disease and childhood asthma,” said Amon. “This guilty plea demonstrates that EPA will vigorously prosecute those who violate laws designed to protect our communities from harmful air pollution.”