Wyoming Sen. Cynthia Lummis (R-Wyoming) has introduced legislation that would effectively undo decades of Environmental Protection Agency (EPA) rules for diesel engines and ban emissions control devices and onboard diagnostic systems.

The “Diesel Truck Liberation Act” was inspired by the story of Wyoming diesel mechanic Troy Lake, who was sentenced to prison for “deleting” emissions systems. Lummis has reportedly sent a letter to President Trump requesting a pardon for Lake. According to Cowboy State Daily, Lake was sentenced to a year in prison in December 2024 for Clean Air Act violations, but he has since been released to serve home confinement.