The California Air Resources Board (CARB) announced Tuesday another round of modifications to its Emergency Vehicle Emission Regulations, first announced last fall after the revocation of EPA waivers for three of its regulations, including its low-NOx Omnibus regulation.
CARB’s low-NOx Omnibus regulation was implemented on Jan. 1, 2024, and operated in the state — despite strong industry pushback — for nearly 18 months before President Donald J. Trump signed a congressional resolution revoking the state’s waiver for the program in June 2025. CARB declared the President’s action unconstitutional at the time and immediately mounted legal and procedural challenges. Returning to the state’s prior emission standards was among CARB’s latter actions, announced last September and then finalized in March.
“Despite the illegal and misguided actions of the federal government to subject Californians to the very real hazards of air pollution, CARB is taking action to ensure that vehicle emissions continue to be held to the same standards required in previous years,” CARB Chair Lauren Sanchez said at the time. “This action will maintain decades of hard-won improvements to new vehicles and engines sold in California, while providing regulatory certainty for manufacturers, stability in the consumer market and protection of public health.”
Since taking that action, CARB has made two amendments to the rules. Tuesday’s announcement indicates a third amendment is required to correct inadvertent errors that were made during the second change process. As such, a 15-day notice of public availability of the modified text began Tuesday and will last until Aug. 5.
CARB wrote Tuesday “until a court resolves the uncertainty created by the federal government’s actions, certain antecedent regulations remain operative (as previously adopted) with the caveat that CARB may enforce ... Omnibus regulations, to the extent permitted by law, in the event a court of law holds invalid the congressional resolutions purporting to disapprove the waivers for those regulations.”
CARB’s updated notice of modified text is available here.
