DEP Suspends Enforcement Of California Heavy-Duty Diesel Emissions Control Program; Federal Standards Will Still Apply

The Department of Environmental Protection published notice in the November 6 PA Bulletin it is suspending the enforcement of the California Heavy-Duty Diesel Emissions Control Program in Pennsylvania through July 31, 2023.

The suspension means the federal standards for heavy-duty diesel vehicles and engines will apply in Pennsylvania.

According to the PA Motor Truck Association, “This means that from this date forward until at least July 31, 2023, members buying new trucks in Pennsylvania will NOT be subject to costly warranty or proposed emissions requirements under CARB [California Air Resources Board], including the 2022 CARB warranty provision PMTA has been advocating to suspend.”  Read more here.

More specifically according to DEP, they will not be enforcing the requirement on model year engines 2022, 2023, and 2024.

There are, however, still concerns from truck manufacturers that the DEP enforcement suspension action would still allow for lawsuits by private groups to enforce the California requirement.

House Bill 2075 (Knowles, R-Schuylkill) was introduced on November 10 to permanently repeal Pennsylvania’s mandate to comply with this CARB requirement.

The PPA supports the suspension and repeal in light of the potential increase in cost of vehicles required to meet the CARB standard.

House Bill 2075 is listed for a vote during a November 15 meeting of the House Environmental and Energy Committee.


In 2002, the Department implemented the then current CARB emission standards for all Heavy-Duty Diesel engines and vehicles that have a gross vehicle weight rating of 14,000 pounds in response to an emissions cheating scandal in the late 1990s, when engine manufacturers installed emission control system defeat devices.

The Program became effective May 11, 2002, and provided the necessary 2 year lead time to manufacturers as required under the federal Clean Air Act. The Program’s emission standards first applied to MY 2005 HDD vehicles and engines.

The Department will re-evaluate this suspension of enforcement no later than July 31, 2023, to determine if the Program is needed to assist the Commonwealth in attainment and maintenance of the National Ambient Air Quality Standards in areas of this Commonwealth and the Ozone Transport Region.

This suspension of enforcement does not create a need for the Department to extend to manufacturers 2 years of lead time to meet the CARB emission standards implemented by the Program if this suspension of enforcement is revoked by the Department.

If the Department revokes this suspension of enforcement for the Program on or before July 31, 2023, manufacturers will be required to meet the Program’s requirements beginning with MY 2025 vehicles and engines.

The Department’s exercise of enforcement discretion does not protect a manufacturer, distributor, seller, renter, importer, leaser or owner of a retail outlet from the possibility of legal challenge by third persons under 25 Pa.?Code Chapter 126, Subchapter E.

Questions about this action should be directed to Mark Hammond, Director for the Bureau of Air Quality, at or 717-787-9702.

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