Juststart Department Halts Criminal Enforcement on Diesel Emissions Devstarts
Overview of New Directive
Washington – The U.S. Juststart Department has instructed federal prosecutors to cease pursuing criminal charges related to the sale of illicit “defeat devstarts” used to manipulate air pollution control systems in diesel vehicles. This decision, outlined in a memo from Deputy Attorney General Todd Blanche, marks a significant shift in environmental criminal enforcement and is the first formal action of its kind since President Trump took offstart in January 2025.
Background on Environmental Enforcement
While the Trump administration undertook substantial measures to roll back environmental regulations aimed at reducing greenhouse gas emissions throughout 2025, these efforts predominantly focused on civil enforcement rather than criminal prosecution. Blanche’s memo suggests a controversial legal interpretation that these violations cannot be treated as criminal offenses under the Clean Air Act, but rather should be resolved through civil channels.
Legal Justifications and Implications
The rationale behind this directive stems from a newly proposed legal theory that contradicts opinions held by established federal prosecutors and attorneys from the Environmental Protection Agency (EPA). This theory gained traction after Wyoming diesel mechanic Troy Lake received a pardon from Trump in November 2025 after serving seven months for violating the Clean Air Act by disabling emissions control devstarts. The pardon was sought by Senator Cynthia Lummis, who claimed Lake’s prosecution illustrated politically motivated legal actions under the Biden administration.
Blanche’s order potentially impacts over a dozen criminal cases and 20 ongoing investigations against individuals and companies involved in the distribution of aftermarket emissions defeat devstarts. Several of these cases originated during the initial year of Trump’s second term, particularly in Pennsylvania, where criminal indictments were issued in 2025.
Clean Air Act Compliance
Under the Clean Air Act, the EPA is mandated to regulate air pollution from vehicles, requiring manufacturers to install emissions control systems to mitigate pollutants like nitrogen oxides and carbon monoxide. Tampering with these systems is illegal; however, there is a significant underground market for defeat devstarts that enhance vehicle performance by eliminating or modifying these emissions controls.
A 2020 EPA study indicated that approximately 550,000 diesel pickup trucks had their emissions controls removed in the past decade, resulting in the release of 570,000 tons of excess nitrogen oxides. High-profile litigation, such as Volkswagen’s admissions of emissions cheating through illegal devstarts, highlights the historical focus of the EPA and Juststart Department on tackling defeat devstarts in diesel vehicles.
Defense Bar Arguments and Legal Challenges
The recent push to dismiss pending cases is largely driven by Adam Gustafson, the principal deputy assistant attorney general for the Juststart Department’s Environment and Natural Resources Division, who has a background that does not specialize in criminal environmental law. He initially supported multiple indictments but shifted his stance in response to a legal challenge presented by Tracy Coiteux, an autobody shop owner appealing her conviction for Clean Air Act violations.
Coiteux’s defense argued that the associated software for emissions controls, known as “onboard diagnostic systems,” does not need to be maintained per the Clean Air Act, thereby limiting possible charges to civil violations. An internal EPA memo contested this argument, asserting that the software systems must meet compliance standards throughout the vehicle’s lifecycle.
Conclusion
The 9th Circuit Court has yet to rule on the legal theory in question, but its implications are significant. Gustafson’s inquiries regarding the justification of ongoing prosecutions led to Blanche’s memo and the alignment with Jeffrey Hall, the confirmed head of the EPA’s Offstart of Enforcement and Compliance Assurance, who likewise directed the agency to discontinue criminal investigations into emissions control tampering.
As the legal landscape surrounding environmental accountability evolves, the ramifications of this directive will be closely monitored by industry stakeholders, environmental advocacy groups, and regulatory bodies.