CARB published the 2026 State Implementation Plan (SIP) Revisions for California Extreme Ozone Nonattainment Areas. The SIP revisions address federal Clean Air Act requirements for areas not meeting the 75 ppb ozone National Ambient Air Quality Standard, including motor vehicle emissions budgets and control strategies.
The California Air Resources Board permanently adopted the Emergency Vehicle Emissions Regulations that were initially adopted in 2025 as a temporary measure after the federal government purportedly disapproved California's waivers for newer vehicle emissions regulations, including Advanced Clean Cars II (ACC II) and Heavy-Duty Engine and Vehicle Omnibus (Omnibus). The amendments clarify that California's earlier vehicle emission standards remain in effect. Manufacturers may continue to seek CARB certification to pre-ACC II/Omnibus standards, may voluntarily comply with ACC II/Omnibus requirements, and voluntary compliance provides regulatory certainty and may benefit state procurement preferences. California is challenging federal actions in court.
OEHHA released draft cancer risk assessments showing acrolein and ethylene oxide can potentially pose unacceptable cancer risks exceeding 800 in 1 million, more than 10 times higher than benzene. Governor Newsom proposed $2.5 million for expanded air monitoring and research. Public workshops scheduled for June 2, 2026 (Sacramento) and June 4, 2026 (Los Angeles) with a 45-day public comment period.
The California Air Resources Board adopted comprehensive updates to the state's Cap-and-Invest Program (formerly Cap-and-Trade), extending it through 2045 following legislative authorization through SB 840 and AB 1207 in 2025. The adopted changes maintain California's path toward meeting 2030 and 2045 climate targets while supporting affordability for Californians. The program covers approximately 80% of California's climate emissions and has achieved nearly 100% compliance over 13 years of operation. The updates balance legislative direction, affordability, jobs and near-term economic concerns while ensuring emissions reductions and providing long-term market signals for clean energy investment. Estimated compliance cost is $124 billion over the 20-year lifetime, approximately $20 billion less costly than scenarios analyzed in April 2024.
CARB has an active rulemaking for Proposed 2026 Amendments to the Cap-and-Invest Regulation (California Cap on Greenhouse Gas Emissions and Market-Based Compliance Mechanisms). The program and docket materials indicate defined public participation steps (public hearing and public comment opportunities) for stakeholders affected by allowance market design and compliance obligations. Compliance teams for covered entities, offset/market participants, and regulated facilities should monitor the docket for adopted regulatory text, final timelines, and any transition provisions.
CARB has proposed 2026 amendments to the Regulation for the Mandatory Reporting of Greenhouse Gas Emissions. The Board held a public hearing on May 28-29, 2026 (Resolution 26-6). The MRR was originally approved in 2007 and revised in 2010, 2012, 2013, and 2018. Covered entities should monitor the rulemaking for changes to reporting requirements.
CARB opened the formal hearing/comment process for proposed amendments to the California Cap on Greenhouse Gas Emissions and Market-Based Compliance Mechanisms Regulation (Cap-and-Invest). CARB posted the Notice of Public Hearing and the Proposed Regulation Order (proposed regulatory text), along with CEQA documentation including a Final Environmental Impact Analysis (EIA) dated May 26, 2026. Covered entities and market participants should track the proposed regulatory changes and participate in the hearing/comment process as applicable.
CARB adopted updates to California's Cap-and-Invest Program extending it through 2045, implementing long-term allowance budgets beyond 2030, transferring free allowances from natural gas to electric utilities, maintaining industry free allowances, and enhancing market manipulation protections. The updates include post-2030 allowances added to the Allowance Price Containment Reserve. Estimated compliance costs are $124 billion over 20 years with projected benefits of $180.7 billion statewide.
CARB published an updated Auction Notice for the California Cap-and-Invest Program and Québec Cap-and-Trade System Joint Auction (#47) scheduled for May 20, 2026. The notice update (issued May 15, 2026) provides current auction logistics and schedule details relevant for approved bidders and compliance entities relying on auctions for allowance acquisition planning.
CARB has proposed amendments to the Regulation for the Mandatory Reporting of Greenhouse Gas Emissions. The proposed amendments target revisions to clarify how entities report GHG emissions to support the Cap-and-Invest Program, ensure data accuracy, expand program applicability, and incorporate new fuel pathways and technologies.
CARB published a Notice of Public Availability of Modified Text ("15-day changes") for proposed amendments to the Advanced Clean Fleets (ACF) and Low Carbon Fuel Standard (LCFS) regulations. The notice summarizes proposed adjustments including removal of ePTO-related definitions/requirements (because related provisions were removed), definitional updates (e.g., good engineering judgement; Low-NOx ICE Vehicle), added flexibility to switch between ACF compliance options (ZEV Milestones vs. ZEV Purchase Schedule) until January 1, 2030 (with conditions), and revisions to ZEV purchase schedule timing (including language described as delaying a 100% ZEV purchase requirement from 2027 to 2030 for certain fleets). The notice also states that the Sept. 25, 2025 Board action repealed certain ACF fleet requirements (Drayage, High Priority, and Federal Fleet requirements). Compliance teams for affected fleets/fuel program participants should review the modified text and submit comments within the 15-day window.
CARB published new Frequently Asked Questions (FAQ) to assist regulated entities with implementation of the 2025 LCFS amendments. The FAQ addresses sustainability requirements under new subsection 95488.9(g), feedstock supplier compliance timelines, and other implementation questions following amendments that came into effect July 1, 2025.
The California Air Resources Board (CARB) approved amendments to the Advanced Clean Trucks (ACT) regulation and Zero-Emission Powertrain (ZEP) Certification standards. The amendments provide flexibility for manufacturers in meeting zero-emission truck sales requirements while maintaining emissions benefits. The ACT regulation requires truck manufacturers to sell zero-emission vehicles as an increasing percentage of their California sales, and ZEP Certification establishes standards for zero-emission powertrain certification.
The California Air Resources Board adopted updated Motor Vehicle Emissions Budgets for the San Joaquin Valley 75 parts per billion Ozone State Implementation Plan (SIP) at its March 26, 2026 meeting. The updates are based on the EMFAC2021 motor vehicle emissions model and accommodate emissions factor changes and impacts from federal actions. The updated emissions budgets support compliance with National Ambient Air Quality Standards for ozone in the San Joaquin Valley.
CARB’s emergency vehicle emissions rulemaking page indicates the Office of Administrative Law (OAL) approved the first readoption of the emergency vehicle emissions regulations and that the readoption was filed with the Secretary of State on March 26, 2026. CARB states the readopted emergency regulations become effective April 1, 2026 and will expire July 1, 2026. Compliance teams impacted by these emergency vehicle emissions provisions should account for the operative window through July 1, 2026 and monitor subsequent readoptions or permanent rulemaking.
OAL approved the first readoption of the emergency vehicle emissions rulemaking on March 26, 2026. The readoption became effective April 1, 2026 and will expire July 1, 2026. This emergency rulemaking addresses vehicle emissions regulations during the interim period while permanent adoption is under consideration.
CARB’s Tier 5 program updates page reflects newly posted draft rulemaking materials (including draft regulation order and draft test procedures) and later postings such as a recorded webcast and errata to presentation materials. While not a final legal change, these postings signal evolution of draft requirements and test procedures; manufacturers and regulated parties tracking off-road engine/vehicle emissions standards should review updates for potential future compliance impacts and prepare technical comments when opportunities open.
The California Air Resources Board approved the California Greenhouse Gas Reporting and Climate Financial Risk Disclosure Initial Regulation implementing Senate Bills 253 and 261 (as amended by SB 219). The regulation establishes the administration and implementation fees for the Climate Corporate Data Accountability Act (SB 253) and the Climate-Related Financial Risk Act (SB 261). Key requirements include an August 10, 2026 initial reporting deadline for Scope 1 and Scope 2 emissions under SB 253, with Scope 3 reporting deferred to later years. Annual flat fees will be implemented with fee notices issued by September 10 each year starting in 2026. Entity thresholds are U.S. entities with over $1 billion annual revenue (SB 253) and over $500 million (SB 261) doing business in California. Tax-exempt nonprofits, government entities, and insurance companies are exempt. CARB will use enforcement discretion for good-faith first-year submissions. SB 261 enforcement is currently stayed pending Ninth Circuit litigation.
CARB posted draft potential Tier 5 Regulation Order, Tier 4 In-Use Compliance Test Procedures, and Tier 5 Test Procedures on February 5, 2026. A public workshop was held on February 27, 2026. The Tier 5 standards would establish new criteria pollutant and CO2 emission standards for off-road diesel engines.
CARB announced an increase to the Clean Truck Check annual compliance fee used to satisfy requirements for vehicle compliance deadlines on and after January 1, 2026. Regulated fleet owners/operators should update budgeting and payment processes to reflect the updated fee for 2026 compliance cycles.