SB 253: First Emissions Reports Due November 10

California's first climate disclosure deadline is days away. Under SB 253, the Climate Corporate Data Accountability Act, U.S. companies with more than $1 billion in annual revenue that do business in California must submit their Scope 1 and Scope 2 greenhouse gas emissions to the California Air Resources Board (CARB) by November 10, 2026. The state's Office of Administrative Law approved CARB's initial regulations on October 12, making the date official, and CARB will accept first-year reports without third-party assurance. Here is who must file, what to send, the options if your data is incomplete and what comes next.

SB 253 in 30 seconds

• Deadline: November 10, 2026, three months after the original August 10 date.
• Who files: U.S.-organized public and private companies with more than $1 billion in total annual revenue that do business in California.
• What to file: Scope 1 and Scope 2 emissions for the prior fiscal year.
• Assurance: CARB will accept 2026 submissions without third-party assurance.
• No data yet: companies that were not collecting, and did not plan to collect, Scope 1 and 2 data as of December 5, 2024 can file a statement of nonreporting instead.
• Next: Scope 3 reporting starts in 2027.

How to file by November 10

Companies can submit through CARB's voluntary online intake platform or by email to climatedisclosure@arb.ca.gov. The first report can draw on existing reports, data gathered for voluntary or other regulatory programs, or CARB's template, and CARB has published submission guidance for 2026. Whatever the format, keep the calculation files, emission factors and data sources behind each number: assurance requirements will follow in later reporting years.

Enforcement and litigation

• First-year flexibility: CARB has said it will use enforcement discretion for companies with incomplete data that make good-faith efforts. That flexibility does not remove the obligation to file, so document what you did.
• Penalties: the law caps administrative penalties at $500,000 per reporting year.
• Court challenges: lawsuits against SB 253 are pending, but its reporting requirements have not been stayed.
• SB 261: the climate-related financial risk reports required by SB 261 are on hold. The Ninth Circuit enjoined enforcement pending appeal, and CARB has said it will not enforce SB 261 while the injunction stands.

What to do this week

1. Confirm you are in scope. Check the $1 billion revenue test and whether the company does business in California under CARB's definitions.
2. Close Scope 1. Fuel combustion, process emissions, fugitive emissions and, in oil and gas, flaring and venting.
3. Close Scope 2. Purchased electricity, steam, heat and cooling, with the emission factors used.
4. Document methods. Record data sources, factors and assumptions in line with the GHG Protocol.
5. Choose the route. A full Scope 1 and 2 report, or a statement of nonreporting if you qualify.
6. Plan for 2027. Map Scope 3 suppliers and get ready for third-party assurance in later cycles.

How Carbonova helps

Carbonova's CarbonOS keeps the inventory and the evidence in one place. Signal Ingest pulls fuel, power and production data from SCADA, ERP and meters; Carbon Intelligence calculates Scope 1, 2 and 3 with traceable methods; and Proof Engine records the lineage of every figure for the assurance provider. In oil and gas, Carbonova Sense monitors flare combustion at the edge; see our guide to OOOOb flare monitoring. Carbonova is a software provider: it does not file reports with CARB or provide assurance. To see your Scope 1 and 2 data in CarbonOS, book a demo.

Who has to file under SB 253 by November 10, 2026?

U.S.-organized public and private companies with more than $1 billion in total annual revenue that do business in California. They report Scope 1 and Scope 2 emissions for the prior fiscal year to CARB.

Is third-party assurance required for the first SB 253 report?

No. CARB will accept 2026 submissions without third-party assurance. Assurance applies in later reporting years, so keep the evidence behind each figure now.

What if my company was not collecting emissions data?

If you were not collecting, and did not plan to collect, Scope 1 and 2 data as of December 5, 2024, you can submit a statement of nonreporting on company letterhead instead of a report.

Does SB 261 still apply?

Not for now. The Ninth Circuit has enjoined enforcement of SB 261 pending appeal, and CARB has said it will not enforce it while the injunction is in effect. The injunction does not cover SB 253.

What software helps prepare SB 253 Scope 1 and 2 reports?

Look for a tool that pulls data directly from meters, utility bills, ERP and plant systems, calculates emissions with documented GHG Protocol methods and keeps an evidence trail an assurance provider can follow. Carbonova AI's CarbonOS does this for heavy industry and also covers Scope 3, which California requires from 2027.

About Carbonova

Carbonova AI (carbonova.ai) is a Brazilian industrial AI company headquartered in São Paulo. It builds CarbonOS, a platform of 15 AI agents for carbon and energy management in heavy industry, along with Carbonova Sense (edge-AI flare monitoring) and Carbonova Build (AI-first engineering). It serves steel, cement, chemicals, mining, oil and gas, energy and agribusiness, with data ready for the GHG Protocol, ISSB, CBAM and Brazil's SBCE. Carbonova AI is not affiliated with Carbonova Corp. of Canada.

Sources

• Cooley (October 14, 2026): California SB 253 November 10 reporting deadline approaching
• Morgan Lewis (October 2026): California's climate disclosure regulations receive final approval
• Linklaters: CARB defers first-year reporting deadline to November 10
• Debevoise & Plimpton (August 2026): CARB clarifies initial SB 253 regulations
• California Legislative Information: SB 253 bill text

Last reviewed: November 2, 2026