EPA Administrator Announces Power-Loss ‘Fix’ for Diesel Exhaust Fluid Systems

by Cami Koons

U.S. Environmental Protection Agency Administrator Lee Zeldin announced guidance Tuesday for engine and equipment manufacturers to prevent sudden shutdowns and power losses that occur in diesel exhaust fluid, or DEF, systems. 

Zeldin made the announcement at the Iowa State Fair and said the current DEF regulations were “unacceptable.” 

“It is unacceptable that farmers, truckers, construction workers, and many other small businesses continually experience failures of diesel-powered equipment when they need it most — costing millions of dollars in lost productivity,” Zeldin said in a statement.

DEF is added to exhaust streams to help reduce the nitrous oxide emissions of burning diesel fuel. EPA rolled out requirements for DEF in the mid 2000s and early 2010s, ensuring that on-road diesel trucks and off-road equipment, like tractors or bulldozers, were equipped with systems that would reduce speed or power of the machinery in the event the machine ran out of DEF. 

According to a press release from EPA these regulations brought the machinery in line with the agency’s emission standards, but caused “significant disruptions in logistics, agriculture, and construction.” In many cases a DEF sensor failure would cause a vehicle to derate to as slow as 5 miles per hour or become inoperable. 

Zeldin’s announcement tasks new diesel on-road trucks, beginning with model year 2027, to be engineered such that running out of DEF will not cause “sudden and severe” power losses. 

EPA has also created guidance to help manufacturers make software changes that will similarly prevent DEF derating on vehicles that are already in use. 

U.S. Sen. Joni Ernst, R-Iowa, called the previous DEF regulations a “Green New Deal” type of regulation that brought tractors to a halt. 

“The previous arbitrary diesel exhaust fluid system guidelines severely hurt farmers, truckers, and small businesses that rely on diesel powered trucks,” Ernst said in a statement. “Not only will the new guidelines save family-run farms hundreds of millions every year, but it is also simply common sense.”

Nitrous oxide, which DEF helps to reduce from diesel exhaust, is categorized by the EPA as having atmospheric warming qualities 265 times greater than carbon dioxide. It also says that 40% of global nitrous oxide emissions come from human activities. 

Zeldin’s plan would not completely eliminate DEF systems, but would significantly extend the amount of time between when the system fails and when machinery capacity is reduced. 

U.S. Small Business Administrator Kelly Loeffler was also at the Iowa State Fair with Zeldin for the announcement and said family farms will save an estimated $727 million annually as a result of the change.

““The Trump Administration is fighting for farmers and truckers, as evidenced by the EPA’s new DEF guidance which is a big win for the millions of small businesses who rely on diesel engines – and who have been crushed by years of costly Green New Scam regulations,” Loeffler said in a statement.

This action comes weeks after EPA officials submitted a proposal to ditch a long-held standing that greenhouse gas emissions threaten the environment and public health.

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