SACRAMENTO, Calif. (AP) -- Republican lawmakers in California are criticizing Democratic Gov. Gavin Newsom because a new law he signed to raise the minimum wage for fast food workers includes an exception that benefits one of his wealthy campaign donors.

California's minimum wage is $16 per hour. But starting April 1, most fast-food restaurants in the state must pay their workers at least $20 an hour under legislation Newsom signed last year to much fanfare. It doesn't apply to restaurants that have on-site bakeries and sell bread as a stand-alone menu item, like Panera Bread.

That exception puzzled some industry watchers and was never fully explained by Newsom or other supporters of the law. But Bloomberg News on Wednesday reported it was connected to opposition from Panera Bread franchisee Greg Flynn, whose company owns 24 of the restaurants in California and has donated to Newsom's campaigns.

The Flynn Group and Flynn Properties operate 2,600 restaurants and fitness centers across 44 states, according to the company's website. Campaign finance records show Flynn Properties and Greg Flynn -- the founder, chairman and CEO -- have donated $223,200 to Newsom's political campaigns since 2017. That included a $100,000 donation to Newsom's campaign to defeat a recall attempt in 2021.

The minimum wage law passed in 2023. In 2022, Flynn had publicly opposed a similar proposal, writing in an op-ed in Capitol Weekly that it would "effectively kill the franchise business model in the state."

A message left with the Flynn Group was not returned on Thursday. Flynn told Bloomberg he did not play a role in crafting the exemption.

Republican leaders in the state Legislature on Thursday blasted the possible connection.

"Put simply, campaign contributions should not buy carveouts in legislation," Republican state Senate leader Brian Jones said. "It's unacceptable."

Assemblymember James Gallagher, the Republican leader in the assembly, said Attorney General Rob Bonta or another entity responsible for investigating conflicts of interest should look into the matter.

"This exemption, there is no explanation for it. Someone had to push for it," he said.

Newsom's office did not provide a comment to The Associated Press. But a spokesperson for his office told the San Francisco Chronicle that the law "was the result of countless hours of negotiations with dozens of stakeholders over two years."

The law was authored by Assemblymember Chris Holden, a Democrat from Pasadena. Holden told reporters Thursday he was not involved in the negotiations over the bill's final amendments, which included the $20 minimum wage increase and the exemption for bakeries. He said those talks happened between the business community and labor unions -- groups Holden said were brought together "through the governor's leadership."

Holden said he did not know Flynn or his status as a Newsom campaign donor. He declined to discuss if there were any legitimate policy reasons for exempting bakeries from the law.

"I'm not going to try to start parceling every individual group," Holden said. "The way that the bill moved forward, everyone who's in is in."

The law represented a compromise between labor unions and business groups. Tia Orr, executive director of the Service Employees International Union California, said the law was "a transformational step toward an economy that works for all, not just billionaires."

"Like all transformational initiatives, it addressed difficult questions around its scope, including what constitutes a fast-food restaurant as opposed to a bakery, for example, and it involved literally hundreds of businesses in discussions," Orr said. "But the big picture is clear: a half million fast food workers in our state now have the power to improve their workplaces."

Dan Schnur, who teaches political communications at the University of Southern California and the University of California, Berkeley, said the issue is reminiscent of when Newsom went to dinner at the French Laundry during the pandemic at a time when he was urging people to avoid public gatherings to prevent the spread of the coronavirus. That issue gave momentum to an effort to recall Newsom from office, which eventually qualified for the ballot in 2021 but was ultimately unsuccessful.

"The last time the governor got in the middle of a restaurant-related controversy, his hesitation to address it turned a small problem into a much bigger one. Hopefully that won't be the case this time, " Schur said. "It's more than possible that there is a perfectly reasonable substantive policy based reason for this exception. But if that reason exists, the governor is obligated to share it with the people of California. Otherwise they'll assume that he did a big favor for a big donor."

Lawmakers are considering more exemptions for the fast-food minimum wage increase. On Thursday, the state Senate approved a bill that would exclude fast-food restaurants in "airports, hotels, large event centers, theme parks, museums, gambling establishments, corporate campuses and certain public lands."

Holden said workers in these restaurants are attempting to negotiate salaries higher than $20 per hour. He said they were concerned being included in the minimum wage law would hurt those negotiations.

"We want to allow for for those industries that can go and get more, to allow them to do so," Holden said.