- DOJ orders prosecutors to drop criminal cases tied to emissions software tampering.
- Civil enforcement under the Clean Air Act will still continue when appropriate.
- The decision could affect dozens of ongoing cases and investigations nationwide.
Over the last few years, the U.S. Department of Justice has spent countless dollars on criminal cases tied to emissions tampering. Now, a new directive makes all that hard work look a bit silly. Moving forward, the department will no longer pursue such cases, and it’s even dropping cases that are currently pending.
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In a memo issued Wednesday by Deputy Attorney General Todd Blanche, the DOJ directed prosecutors to stand down regarding allegations of illegally modifying emissions control software. In other words, devices that enable vehicles to skirt the Clean Air Act are no longer in the crosshairs.
A Shift in Federal Priorities
According to CBS News, Blanche justified the decision by citing a new legal theory that argues tampering with emissions-related software does not meet the Clean Air Act’s threshold for criminal prosecution, and should instead be treated as a civil violation. That position runs counter to long-held interpretations by career prosecutors and EPA attorneys, some of whom have warned internally that the legal reasoning is flawed.
The move could impact more than a dozen active criminal cases and over 20 ongoing investigations across the country, many of which targeted aftermarket companies and individuals accused of selling or installing emissions defeat devices on diesel trucks. Several of those cases were indicted as recently as 2025.
Emissions tampering has long been a priority for regulators due to its environmental impact. A 2020 EPA study estimated that emissions controls had been removed from roughly 550,000 diesel pickup trucks over the prior decade, resulting in approximately 570,000 tons of excess nitrogen oxides.
The department says it will continue pursuing civil enforcement actions alongside the Environmental Protection Agency when warranted. That’s key because it means that some big companies could still face fees and penalties.
In addition, it’s worth noting that local and state laws could put drivers of modified vehicles in hot water. Tampering is still technically illegal from a federal perspective. The difference now is that the DOJ won’t come knocking.