Overview
- The Environmental Protection Agency announced the proposal Thursday to amend the 2023 heavy‑duty truck rule by removing automatic DEF‑triggered engine deratements, shortening emissions warranties, and delaying some mileage triggers.
- The agency said the changes would save the trucking industry about $12 billion overall and as much as $6,000 per new truck by reducing up‑front costs and easing supply chain pressures.
- Under the proposal the headline NOx limits from the Biden rule remain in place while warranty requirements would shrink from the longer 450,000‑mile period back toward roughly 100,000 miles and some useful‑life compliance dates would be pushed later.
- Critics including the Environmental Defense Fund say the edits would weaken enforcement that makes limits meaningful and harm public health, while agency modelling cited in coverage suggests the rollback would raise NOx over time and could undo some avoided hospital visits and asthma cases projected under the 2023 rule.
- The measure is not final, will undergo a public comment period and is likely to draw legal and political challenges from states, environmental groups and other stakeholders that could shape its ultimate form.