Senate bill seeks to end prosecution for diesel emissions control ‘deletes’ and ‘tunes’
A Wyoming Senator introduced legislation that would put a stop to enforcement of diesel emissions control tampering rules.
On October 15, 2025, Senator Cynthia Lummis introduced “The Diesel Truck Liberation Act,” a bill that seeks to protect individuals from prosecution for removing or altering emissions control devices in diesel trucks, a practice often referred to as a “tune” or a “delete.”
Lummis said that if passed, the bill would “end the Obama and Biden EPA’s war on truck owners and mechanics.”
The bill includes the following four provisions:
- Prohibits the federal government from requiring manufacturers to install or maintain emissions control devices or onboard diagnostic systems.
- Removes EPA authority to enforce Clean Air Act requirements related to vehicle emissions controls.
- Individuals cannot be prosecuted or sued under federal law for tampering or improving emissions equipment.
- Vacates existing prison sentences for emissions-related violations and expunges criminal and civil records related to these offenses.
Lummis said that she was inspired to introduce the bill by the story of diesel mechanic Troy Lake, a Colorado business owner who was sentenced in December 2024 to 12 months and 1 day in custody and a fine of $2,500 after he pleaded guilty to conspiring to violate the U.S. Environmental Protection Agency’s (EPA) Clean Air Act.
In pleading guilty, Lake admitted to instructing employees to disable the computerized on-board diagnostic (OBD) systems on at least 344 heavy-duty commercial trucks, which violates the Clean Air Act’s prohibition against tampering with monitoring devices.
“The Biden EPA threw Troy Lake and other mechanics in prison for keeping school buses, fire trucks, and ambulances running in cold, harsh climates,” said Lummis. “When Washington bureaucrats can make you a criminal without Congress ever voting on it, we have a huge problem. I want this overreach to end. Democrats weaponized the EPA to wage war on rural America, and we cannot let that happen again. This legislation is the first step toward justice and sanity.”