California SB 253/261 Update – CARB’s 2026 Initial Regulation Nears the Finish Line

The California Air Resources Board resubmitted its final rulemaking package for the SB 253/261 Initial Regulation to the California Office of Administrative Law on September 21.
 
The Initial Regulation establishes the fee program, the SB 253 November 10, 2026 reporting deadline and the definitions of “revenue” and “doing business in California,” among other things.
 
CARB has requested that the OAL establish an “earlier effective date,” i.e., that the Initial Regulation take effect upon filing with the California Secretary of State.
 
As noted in CARB’s Addendum to the Final Statement of Reasons for Rulemaking, the Initial Regulation resubmitted to the OAL includes only a handful of additional non-substantive changes since CARB’s 15-Day Notice, which was released on July 27. The bulk of the Addendum addresses the additional written comments submitted during the comment period that followed the 15-Day Notice (from 21 commenters) and CARB’s responses.
 
CARB did not make any changes to the Initial Regulation in response to the comments. However, many of the comments submitted were not specific to the modifications made to the Initial Regulation through the 15-Day Notice. They instead relate to CARB’s more significant second rulemaking, which will apply to SB 253 reporting in 2027 and subsequent years, and will be considered as part of that rulemaking process.
 
As many readers of these posts will recall, CARB had previously submitted the final rulemaking package to the OAL on May 20, for review in accordance with the California Administrative Procedure Act. CARB withdrew that rulemaking package on June 23. Modified regulatory language and supporting documentation were subsequently circulated for a 15-day public comment period that ran from July 27 to August 11.

CARB's most recent 2026 reporting guidance and its voluntary reporting platform for 2026 reporting are discussed in this Ropes & Gray post.

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