TEXAS AGRICULTURE COMMISSIONER SID MILLER APPLAUDS EPA ACTION TO END HARMFUL DIESEL EXHAUST FLUID SHUTDOWNS

August 15, 2025 – AUSTIN – Texas Agriculture Commissioner Sid Miller today praised the U.S. Environmental Protection Agency (EPA) for their decisive action in issuing new guidance that protects farmers, truckers, and other diesel equipment operators from sudden speed and power losses caused by diesel exhaust fluid (DEF) systems without compromising environmental protection standards.

What is DEF?

• DEF is a non-toxic solution of urea and deionized water injected into the exhaust stream of diesel vehicles.
• It works with the Selective Catalytic Reduction (SCR) system to reduce harmful nitrogen oxide (NOx) emissions.
• Without DEF, a diesel vehicle would not meet federal emissions standards, and the engine might not start. 

“For years, I’ve heard from Texas farmers, ranchers, and truckers who have been sidelined by ridiculous DEF shutdowns in the middle of planting, harvest, or hauling,” Commissioner Miller said. “This nonsense has cost our producers time, money, and peace of mind. This decision by Administrator Zeldin is a victory for common sense and yet another sign that, under President Trump, Washington is finally listening to rural America.”

What happens when DEF runs out?

• Modern diesel vehicles are equipped with systems that monitor DEF levels. 
• If DEF is low, the vehicle’s performance may be reduced through a “derate” process, limiting speed or power. 
• In the past, running out of DEF could lead to sudden and complete engine shutdowns, which was problematic for farmers, truckers, and other businesses. 

The announcement, made by EPA Administrator Lee Zeldin alongside U.S. Small Business Administrator Kelly Loeffler at the Iowa State Fair, directs engine and equipment manufacturers to revise DEF system software in existing vehicles and equipment. This update will prevent abrupt shutdowns and give operators more time to address maintenance needs—ensuring productivity and safety in the field and on the road.

Current DEF shutdown rules are estimated to cost family farms and small businesses roughly $727 million annually through lost productivity, repair and service expenses, missed deadlines, penalties for late deliveries, and crop quality losses when harvest windows are missed.

“Texas agriculture runs on hard work and diesel power, not government red tape,” Miller added. “This action will strengthen the economy of rural Texas and finally give our farmers and ranchers the relief they’ve been asking for. This new EPA guidance will save farmers millions, prevent costly equipment shutdowns, and keep Texas agriculture moving forward.”