President Donald Trump has pardoned nine individuals convicted of violating the Clean Air Act by tampering with diesel vehicle emissions-control systems. Trump announced six of the pardons on his social media platform, Truth Social, stating that the individuals were persecuted by the Biden Administration and punished for "fixing their car."
Eight of those pardoned were diesel mechanics or tuners prosecuted for selling and installing "defeat devices." These devices reprogram trucks to bypass federally mandated emissions controls. Without these devices, many diesel trucks enter a "limp" mode that significantly reduces their speed until the emissions system is restored.
According to a Fox News review of federal court records, one recipient, Matthew Geouge, operated two companies that sold these illegal tuning devices, generating over $10 million in gross sales, as detailed in his December 2021 plea agreement. Another recipient, MacKenzie "Mac" Spurlock, a mechanic in Alaska, modified emissions controls for vehicles due to malfunctions with Diesel Exhaust Fluid (DEF) systems, which are prone to issues in cold weather. Senator Dan Sullivan, R-Alaska, stated that Spurlock's shop assisted trucking businesses by modifying these systems to ensure vehicles would not shut down in Alaska's subzero conditions. Sullivan described the raid on Spurlock's business as a "military-style tactical raid" conducted by EPA agents.
Emissions-capping technology, particularly DEF systems, have been a significant source of maintenance issues and costs for state-owned diesel vehicles in Alaska, according to a state equipment fleet manager. A transportation service president in Alaska reported that DEF systems account for approximately 85 percent of their vehicle breakdowns.
The other individuals granted pardons for similar offenses include Ryan and Wade Lalone, Tim Clancy, Joshua Davis, Barry Pierce, Aaron Rudolf, and Jonathan Achtemeier.
In late January 2026, the Trump administration announced it would cease pursuing criminal charges against manufacturers, distributors, and users of defeat devices, although civil penalties could still apply.