The lawmaker behind California's recently vetoed AI bill, SB 1047, is going down swinging.

For months, Silicon Valley debated whether SB 1047 would have a chilling effect on California's AI boom or would protect against catastrophic harms from advanced AI systems. The answer never became clear, since California governor Gavin Newsom decided it was the wrong approach, vetoing the bill on Sunday before it became law.

Now California state senator Scott Wiener tells TechCrunch that some Silicon Valley institutions spread an unprecedented level of "misinformation" about SB 1047 in the months leading up to the veto. (Folks outside of Silicon Valley also criticized SB 1047, including Nancy Pelosi and the U.S. Department of Commerce.)

"I've had tough bills before, and bills where there have been misinformation. I've never had a bill with this level of misinformation," Wiener told TechCrunch. "There was a whole propaganda campaign."

Wiener specifically criticized Y Combinator and Andreessen Horowitz executives for helping spread a narrative that SB 1047 would send startup founders to jail. This is not technically false; theoretically, a developer who lied on AI safety reports that SB 1047 would have required could have gone to jail for committing perjury. But that would only have happened if a developer had lied.

Indeed, some in the tech industry helped spread that idea. In June, Y Combinator CEO Garry Tan signed a letter to California lawmakers claiming that "AI software developers could go to jail" under SB 1047. Earlier that same month, Andreessen Horowitz partner Anjney Midha said in a podcast that "no rational startup founder or academic researcher is going to risk jail time or financial ruin just to advance the state of the art in AI."

"A16Z was, I think, at the heart of a lot of the opposition to the bill," Wiener said.

Y Combinator's head of public policy, Luther Lowe, tells TechCrunch that the debate around SB 1047 is not as clear cut as Wiener makes it out to be.

"The semantic debates alone demonstrate the challenges with bills like SB 1047 being vague and open-ended," said Lowe in an email.

Andreessen Horowitz pointed TechCrunch toward a letter its chief legal officer wrote months earlier when Wiener made similar claims, stating that SB 1047 "is a deeply troubling and fundamental departure from the way software development has been regulated in this country."

Another claim Wiener called out as misinformation was that SB 1047 would push AI startups out of California. Wiener claims startups across the country would have been affected equally by SB 1047, as long as they did business in California.