US EPA proposes easing Biden heavy-truck emissions rules

The US Environmental Protection Agency has proposed easing heavy-truck and engine emissions regulations, allowing the sale of non-compliant engines while manufacturers complete development of 2027-compliant models.

The ​U.S. Environmental Protection Agency on Thursday proposed easing heavy-truck ​and engine emissions regulations adopted under Democratic ‌President Joe Biden ​in 2023 and will allow the sale of some engines that do not meet the tougher tailpipe rules. The EPA said it was proposing scaling back emissions warranty ‌requirements and providing additional lead time before longer regulatory useful life requirements take effect.

The EPA, which noted that some 2027 medium and heavy-duty engine development programs have experienced technical challenges, is proposing allowing manufacturers to continue to sell current products while they ‌complete development of 2027-compliant engines. EPA said that even with its proposed changes, the decline in smog-forming nitrogen oxides (NOx) still would ‌be nearly 90% of forecasted reductions under the Biden emission standards. EPA Administrator Lee Zeldin said the existing requirements were unworkable, would drive up costs and result in fewer choices. He said the rule is estimated to save $12 billion, or as much as $6,000 per truck. Environmental groups argue the ⁠proposed changes ​will increase pollution and harm ⁠public health. “This Trump EPA proposal to weaken vital clean air protections will mean more health harms and higher costs,” said the Environmental Defense Fund in ⁠a statement. “EPA should abandon this proposal and instead maintain strong pollution safeguards for new heavy-duty vehicles.” The EPA is proposing penalties for some ​heavy-duty diesel engines that temporarily cannot meet the Biden standards, while allowing sales to continue. The Trump administration has taken a ⁠number of actions to reverse Biden rules to require more electric vehicles and cleaner vehicles. Last month, the EPA sent the Republican-controlled Congress landmark California vehicle ⁠emissions ​rules for potential repeal, its latest effort to prevent tougher state tailpipe requirements. The Trump administration has also enacted rules making it easier for automakers to sell more gasoline-powered cars and trucks, while making it more expensive to buy EVs. The White ⁠House also significantly weakened federal tailpipe rules. Congress passed legislation in 2025 to stop collecting penalties for not meeting vehicle ⁠tailpipe standards, saving automakers hundreds ⁠of millions of dollars for selling vehicles that were not in compliance with pollution rules. The EPA in February separately repealed a scientific finding that greenhouse gas emissions endanger human health, ‌and eliminated federal tailpipe ‌emissions standards for cars and trucks.