CARB Finalizes Initial SB 253 Rules; First Climate Filing Deadline November 10
California's approval of CARB's initial SB 253 regulation effective October 12, 2026 sets a November 10 filing date for Scope 1 and 2 emissions, with a fee framework, updated guidance and a voluntary submission portal now in place.
Per an Akin Gump client alert, the California Office of Administrative Law has approved CARB's initial regulation implementing SB 253, effective October 12, 2026. The rule, originally adopted by CARB in February, establishes an initial fee framework and formalizes November 10, 2026 as the first reporting deadline for Scope 1 and Scope 2 greenhouse gas data; Scope 3 reporting is scheduled to begin in 2027. SB 253 generally reaches U.S.-based companies with more than $1 billion in annual revenues that do business in California. CARB has opened a voluntary online submission platform for contact details and Scope 1 and 2 reports, with email as an alternative, published updated reporting guidance in September 2026, and issued reminder letters to potentially covered entities.
Practically, the platform is optional but the deadline is not. Covered companies should confirm applicability and revenue-threshold scoping, finalize emissions data with audit-ready controls, and select a submission route before November 10. Two unresolved variables warrant watching: pending legal challenges to SB 253 and broader federal efforts to scale back mandatory GHG reporting, leaving federal-state divergence unsettled and creating the possibility of further adjustment to scope, timing or fees.