Nebraska Attorney General sounds alarm on DEF system safety risk for truckers

The Nebraska Attorney General’s Office (NAGO) issued an alert about reported safety issues with diesel exhaust fluid (DEF) systems operated by truckers.

The alert issued on February 4, 2026, warns Nebraskans that “DEF systems are present in diesel engines and equipment often used by farmers, truckers, and motorists. Consumers should note that their current DEF equipment may present safety risks, such as sudden speed loss and shutdowns.”

The alert was issued following recent actions taken Environmental Protection Agency (EPA) to address DEF derates. In August 2025, the EPA issued guidance to engine manufacturers to update DEF system software to curb sudden shutdowns and slowdowns. However, officials said that DEF system failures are ongoing and still impacting truckers, farmers, and other diesel equipment users. In an effort to address the ongoing DEF issues, the EPA issued new guidance this week demanding diesel engine manufacturers to provide information on DEF failures and associated safety issues.

“The Nebraska Attorney General’s Office supports EPA’s efforts to keep farmers, truckers, and other diesel operators safe. Our office will help ensure these safety risks are addressed by manufacturers. Farmers, truckers, and everyday consumers deserve safe, reliable diesel equipment and vehicles,” officials said.

The NAGO’s DEF safety alert advises Nebraskans to take the following precautions:

• Contact your diesel engine or equipment manufacturer to ensure your diesel trucks and equipment meet the new EPA guidelines. Software updates may be necessary to resolve these ongoing safety concerns.
• You have the right to repair your equipment to prevent safety issues. The EPA issued guidance on how consumers may self-repair and modify DEF systems to avoid issues.
• Ensure your equipment or vehicle DEF is not low or at risk of running low, especially when operating in conditions or distances that would be unsafe if a slowdown or shutdown were to occur.

Nebraskans experiencing DEF issues are also encouraged to report problems to ProtectTheGoodLife.Nebraska.gov.