SACRAMENTO  (AP) — California lawmakers approved legislation Friday that would allow illegal immigrants to voluntarily join a program and pay state income taxes in exchange for leniency in their immigration status.

The state Assembly approved SB901 by Senate President Pro Tem Darrell Steinberg, D-Sacramento, on a 42-30 vote, sending it to the governor.

Supporters say encouraging more illegal immigrants to pay taxes could generate more than $300 million annually, but the state Franchise Tax Board said the legislation would likely have no effect on state revenue.

Workers would need to apply to the state to be part of the five-year pilot program and meet certain criteria, including not being convicted of a felony, learning English and living in California at least since 2008.

In exchange for filing and paying the taxes they owe, California would ask the federal government to put them in the lowest tier of immigration enforcement. The program would not launch if federal officials did not agree.

"The bill attempts to ask the federal government to recognize these most desirable ... and identify them as the lowest tier of prosecution. No more, no less," said Assemblyman Felipe Fuentes, D-Sylmar.

Opponents called the plan a form of amnesty and noted that illegal immigrants are already required by law to pay state income taxes, and about 1 million of California's estimated 1.8 million illegal immigrants already do.

"So I would say that this is not about even helping illegal immigrants in any way shape or form from doing things that they're not already doing, what it does is provide for safe harbor," said Assemblywoman Diane Harkey, R-Dana Point.