The Environmental Protection Agency (EPA) has proposed scaling back several pollution-control requirements for heavy-duty vehicles, including buses, semis, garbage trucks, and fire engines.
The agency said on Thursday that it would revise parts of a Biden-era clean-air rule that established stricter standards for heavy-duty engines beginning with model year 2027.
The proposal would shorten mandatory warranties for emissions-control systems, delay requirements governing how long engines must continue meeting emissions standards, and eliminate mandatory power and speed reductions when certain pollution-control systems malfunction.
The underlying model-year 2027 tailpipe standards for nitrogen oxides, or NOx, would remain in place, meaning manufacturers would still have to meet substantially tighter limits on pollution from new engines.
EPA Administrator Lee Zeldin said the changes could ultimately lower costs for consumers by making transportation less expensive.
“Even if you’ve never driven a truck in your life, when it costs less to move goods, it costs less to buy them,” Zeldin said Thursday at the Great American State Fair on the National Mall in Washington. “Those savings get passed down to you at the grocery store and the hardware store on nearly everything a truck delivers.”
“We protect the air. We protect your pocketbook,” Zeldin said on Thursday. “It doesn’t have to be one or the other.”
Major Proposed Changes
One of the biggest proposed changes concerns warranties for emissions-control equipment.For the heaviest diesel engines, the Biden-era rule would have required manufacturers to cover emissions-related components for 450,000 miles or 10 years. The Trump administration is proposing to retain the existing requirement of 100,000 miles or five years instead.
Warranty periods for other classes of heavy-duty engines would also remain at their current, shorter levels rather than increasing beginning with model year 2027.
The Biden administration had said that longer warranties would encourage owners to repair faulty pollution-control systems and give manufacturers a financial incentive to make the equipment more reliable. The current EPA, however, said those potential emissions benefits do not outweigh the higher costs associated with longer warranties.
According to the agency’s analysis, shortening the warranty requirements would save between $4,130 and $6,152 for each new diesel engine affected, depending on the vehicle class. The estimated savings amount to $5,358 for the heaviest diesel engines and $6,004 for urban bus engines.
The EPA is also proposing to delay a requirement governing the “useful life” of emissions-control systems.
Under the Biden-era rule, the heaviest truck engines would have had to demonstrate compliance with emissions standards for up to 650,000 miles beginning with model year 2027. The proposal would keep the existing 435,000-mile requirement in place for model years 2027 through 2029, with the longer requirement taking effect in model year 2030.
The three-year delay, according to EPA, would give manufacturers more time to gather real-world durability data and refine their emissions systems before becoming responsible for compliance over the longer period.
Another proposed change targets the system used to pressure drivers to repair problems involving selective catalytic reduction systems, which use diesel exhaust fluid, or DEF, to reduce emissions.
Current rules can require engines to gradually reduce power or limit vehicle speed when the system detects certain problems. The EPA is proposing to eliminate mandatory performance derates and replace them with a visible or audible alert to drivers.
The administration acknowledged that the changes would come with some environmental trade-off.
Compared with leaving the Biden-era rule unchanged, the EPA estimated that implementing the changes would increase NOx emissions from heavy-duty vehicles by an estimated 4.2 percent in 2030 and 11.6 percent by 2055. Almost all of that increase would result from eliminating the longer emissions-warranty periods.
Industry Groups Back Proposal, Environmentalists Object
The proposal drew support from the trucking industry and small-business groups.Kelly Loeffler, head of the U.S. Small Business Administration, said the changes would alleviate “burdensome diesel regulations on behalf of farmers, truckers, and small business owners who were crushed by unworkable environmental activist demands that became costly mandates.”
The American Trucking Association had called for changes to the NOx standards, specifically urging the agency to allow truck manufacturers to pay penalties rather than immediately comply with the standards, provided they were still working to develop compliant engines. The EPA included such an option in Thursday’s proposal.
Environmental advocates, meanwhile, criticized the proposal, saying additional pollution would harm public health.
“This Trump EPA proposal to weaken vital clean air protections will mean more health harms and higher costs in communities across the country,” said Peter Zalzal, associate vice president for clean air strategies at the Environmental Defense Fund.
“Heavy duty diesel vehicles like freight trucks and buses emit huge amounts of smog and soot-forming pollution into the air we breathe, but truck makers are already introducing new engines that can substantially cut this pollution and meet protective standards.”
Nitrogen oxides are produced primarily by the burning of fuel and contribute to the formation of smog, according to the EPA. Exposure to elevated concentrations of nitrogen dioxide can irritate the respiratory system and aggravate conditions such as asthma.
