SB 253/SB 261 Update: What CARB’s 15-Day Modifications Mean for Business Compliance Plans
U.S.-based entities with at least $1 billion in global annual revenue that do business in California should revisit their 2026 SB 253 compliance plans following the release, by the California Air Resources Board (CARB), of 15-day modifications to its proposed regulations. The modifications provide additional time and flexibility within the first program year, allow parent companies to submit consolidated reports, and clarify how companies should assess whether they are covered.
SB 253 Update: CARB Delays Reporting Deadline to November 2026 and Proposes to Clarify Requirements
Companies preparing to comply with California’s Senate Bill (SB) 253 and submit their first required disclosures in August 2026 have received an update this week from the California Air Resources Board (CARB) that will delay reporting deadlines. On June 24, 2026, CARB deferred the deadline for entities to report Scope 1 and Scope 2 greenhouse gas (GHG) emissions from August 10, 2026 to November 10, 2026. The three-month deferral will provide additional time for reporting entities following the anticipated approval and formal adoption of CARB’s proposed regulation. CARB will propose limited changes to the regulation to clarify requirements. These changes will be made available for comment in a forthcoming 15-day public comment period.
SB 253 Update: CARB Still Wrestling With Draft Regulations in March 2026
Companies preparing to comply with California’s SB 253 and submit their first required disclosures in August 2026 received additional guidance this week from the California Air Resources Board (CARB). At a public workshop on March 23, CARB outlined proposed approaches under its developing rulemaking, including options for phasing in compliance over time, and solicited public feedback on those concepts. The following article summarizes the key developments from that workshop.
CARB Proposes to Repeal Advanced Clean Fleets Regulation
The California Air Resources Board (CARB) has proposed to repeal the High-Priority and Drayage components of the Advanced Clean Fleets (ACF) regulations. The proposal also includes changes to the Low Carbon Fuel Standard (LCFS) regulations and implements AB 1594 (flexibility for public utilities).
States Propose New Indirect Source Rules Targeting Warehouse Emissions
A growing number of states are advancing indirect source rules (ISRs), making warehouse and related logistics operations responsible for reducing or offsetting air pollution from the vehicles that transport goods to and from the covered warehouses. California’s South Coast Air Quality Management District (SCAQMD) has already adopted Rule 2305 — affecting warehouses in the Los Angeles region — and new legislative and regulatory proposals may soon expand similar obligations statewide in California and to other jurisdictions. These measures aim to address pollution from mobile sources, such as trucks that frequent warehouse hubs indirectly, and require a suite of costly measures aimed at transitioning fleets away from diesel fuels and internal combustion engines. Although these proposals directly regulate warehouse owners and operators, they aim to transition fleets to alternative energy sources by imposing costs for warehouse visits.
Environmental Groups Bring CEQA Challenges of CARB’s Amendments to the Low Carbon Fuel Standard
Earlier this week, two environmental groups sued the California Air Resources Board (“CARB”) for approving amendments (the “Amendments”) to the Low Carbon Fuel Standard (“LCFS”). CARB had voted to amend the LCFS on November 8, 2024, with the intent of lowering the carbon intensity of the fuel mix in California and encouraging the use of low-carbon transportation fuels. For more details on the LCFS Amendment changes, see Sidley’s Alert.
17 States File Complaint Challenging Constitutionality of California’s Advanced Clean Fleets Regulation
On May 13, 2024, 17 states filed a complaint in the U.S. District Court for the Eastern District of California challenging California’s Advanced Clean Fleets (ACF) regulation.
California Air Resources Board Will Workshop Omnibus Regulation Amendments
The California Air Resources Board (CARB) announced that it will hold a public workshop to discuss amendments to its Heavy-Duty (HD) Engine and Vehicle Omnibus (Omnibus) Regulation. The amendments have been proposed following extensive discussion between CARB and the Engine Manufacturers Association (EMA) during 2023, which culminated in CARB agreeing to revise its heavy-duty vehicle emission standards to align more closely with U.S. Environmental Protection Agency standards.
California Air Resources Board Issues Clean Truck Check Implementation Guidance
On August 23, 2023, the California Air Resources Board (CARB) published additional guidance for the implementation of Clean Truck Check requirements under its Heavy Duty Inspection/Maintenance regulation. The requirements build on implementation guidance issued in June and set deadlines to achieve compliance with certain requirements beginning by December 31, 2023. Fleet owners and operators, and those contracting or brokering loads with heavy-duty trucks, should take note of CARB’s implementation timeline and prepare to comply with reporting and fee payment requirements beginning in the fourth quarter of 2023.
California Air Resources Board Revisits Advanced Clean Fleets Rule Through Formation of Truck Regulation Advisory Committee
In April 2023, the California Air Resources Board (CARB) passed its Advanced Clean Fleets (ACF) rule, which will require California medium- and heavy-duty truck and bus fleet owners with over $50 million in annual revenue to transition to zero emission vehicles through a phaseout of their existing internal combustion engine–powered vehicles by 2045. On July 26, 2023, while the ACF rule was pending with the California Office of Administrative Law for a final determination prior to release, CARB withdrew the regulatory package with the intention of resubmitting it “at a subsequent date.” CARB is now forming a Truck Regulation Advisory Committee and, on August 22, 2023, will host a public meeting to discuss and solicit feedback on future efforts to implement the ACF rule. Instructions for participation in this public meeting can be found here.
