SAN FRANCISCO — California Gov. Gavin Newsom signed a first-in-the-nation law on Monday that will force major AI companies to reveal their safety protocols — marking the end of a lobbying battle with big tech companies like ChatGPT maker OpenAI and Meta and setting the groundwork for a potential national standard.

The proposal was the second attempt by the author, ambitious San Francisco Democrat and state Sen. Scott Wiener, to pass such legislation after Newsom vetoed a broader measure last year that set off an international debate.

It is already being watched in Congress and other states as an example to follow as lawmakers seek to rein in an emerging technology that has been embraced by the Trump administration in the race against China, but which has also prompted concerns for its potential to create harms.

“California has proven that we can establish regulations to protect our communities while also ensuring that the growing AI industry continues to thrive. This legislation strikes that balance,” Newsom said in a statement announcing the signing.

“AI is the new frontier in innovation, and California is not only here for it — but stands strong as a national leader by enacting the first-in-the-national frontier AI safety legislation that builds public trust as this emerging technology rapidly evolves.”

The measure, SB 53, requires some AI developers to publicly disclose their safety and security protocols. It also creates a way for companies and the public to report major safety incidents to the state. The law includes whistleblower protections for AI workers and lays the groundwork for a state-run cloud computing cluster dubbed CalCompute.

“With a technology as transformative as AI, we have a responsibility to support that innovation while putting in place commonsense guardrails to understand and reduce risk,” Wiener said in a statement. “With this law, California is stepping up, once again, as a global leader on both technology innovation and safety.”

Newsom last week had hinted he would sign the bill while speaking at an international panel event with former President Bill Clinton, on the sidelines of the U.N. General Assembly — illustrating how significant the measure could be, even beyond California’s borders.

Signing the law could also help further distinguish Newsom — a likely 2028 contender — from President Donald Trump, whose administration has worked to accelerate AI development as a way to beat China in the tech race.

Some of the bill’s provisions are a policy first anywhere in the world. For example, the law requires public disclosure of security plans and protocols, while the EU AI Act requires such measures to be privately sent to governments.

Companies are also required to report incidents related to crimes committed without human oversight — like cyber attacks — and deceptive behavior by a model that isn’t required under the EU scheme.

The signing is a highly-visible victory for Wiener, who himself has his eye on national office and has already filed papers to run for Rep. Nancy Pelosi’s San Francisco seat in Congress. The win comes after Newsom vetoed his more expansive SB 1047 last year amid major backlash from tech companies that argued it would have hindered the booming AI industry in California.

This time around, Wiener appealed directly to major AI companies about his narrower legislation, worked with Newsom’s office and tailored the legislation around a report the governor had commissioned this year from AI safety experts on how to regulate the technology.

Major AI labs OpenAI and Meta did not publicly oppose Wiener’s new bill, while Anthropic, maker of the Claude chatbot, backed the measure in the waning days of the legislative session.

Meta spokesperson Christopher Sgro said after Newsom’s signing that the company “supports balanced AI regulation,” calling the new law “a positive step in that direction.”

“We look forward to continuing to work with California lawmakers to ensure AI regulations protect consumers and society while fueling innovation and economic growth in the state and across the U.S.,” Sgro added.

Anthropic’s co-founder Jack Clark said: “We’re proud to have worked with Senator Wiener to help bring industry to the table and develop practical safeguards that create real accountability for how powerful AI systems are developed and deployed.”

OpenAI spokesperson Jamie Radice said the company was “pleased to see that California has created a critical path toward harmonization with the federal government — the most effective approach to AI safety. If implemented correctly, this will allow federal and state governments to cooperate on the safe deployment of AI technology.”

Meanwhile, tech industry lobbying group Chamber of Progress continued to slam the measure, however, comparing it to Wiener’s effort last year and saying it would harm the state’s leading innovation economy.

“California has always offered a fair shot for new innovators — that’s exactly why our tech sector has flourished,” said Robert Singleton, the group’s senior director for California, in a statement. “But this could send a chilling signal to the next generation of entrepreneurs who want to build here in California.”

Collin McCune, head of government affairs at venture capital firm Andreessen Horowitz, wrote on X that the bill included “some thoughtful provisions that account for the distinct needs of startups.”

But, he added, it “misses an important mark by regulating how the technology is developed — a move that risks squeezing out startups, slowing innovation, and entrenching the biggest players.” The measure sets a precedent for states, rather than the federal government, to regulate AI, McCune said.

“Smart AI regulation can help us win the AI race, but we need the federal government to lead in governing the national AI market.”

Similar legislation was passed by state lawmakers in New York, but still needs to go through Gov. Kathy Hochul for a final say on whether it becomes law.

Meanwhile in Congress, Republican Sen. Ted Cruz has spearheaded an effort to freeze state AI legislation, vowing to revive the effort after it initially failed to make it into the megabill passed over the summer. Other members of Congress have separately discussed crafting a national AI safety framework with potential carve-outs for state rules.

A spokesperson for Cruz declined to comment on Newsom’s bill signing, but pointed to comments the senator had made earlier this month at an AI event.

“There is no way for AI to develop reasonably, and for us to win the race to beat China, if we end up with 50 contradictory standards in 50 states — and not just 50 states because cities and municipalities will do this too,” Cruz said at the Axios AI summit.

“Do you really want Gavin Newsom and Karen Bass and Comrade Mamdani in New York City setting the rules for AI and governing AI across this country? I think that would be cataclysmic.”