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….