California could become the first state to outlaw so-called puppy mills with legislation that bans pet stores from selling dogs, cats and rabbits that do not come from rescue organizations or shelters.

California legislators passed the bill, AB 485, on Thursday and sent it to Gov. Jerry Brown, who has until Oct. 15 to act.

The bill laid bare the divisions among animal rights advocates, breeders and pet store owners. Opponents said the bill would put pet stores out of business and deny consumer protections to the public, while supporters said it will cut off a pipeline of animals bred under inhumane conditions.

The Pet Industry Joint Advisory Council called on Brown to veto the bill.

“Pet lovers deserve to know the medical history of their prospective pet, and to have recourse under certain circumstances if the pet is ill or dies due to illness,” it said in a statement.

Dustin Siggins, a spokesman for the Pet Industry Joint Advisory Council, said supporters “unfairly demonize all commercial breeders.”

Opponents said the measure would put pet stores out of business because it did not require shelters and rescue organizations to provide animals to stores.

“Hundreds of pet professionals’ jobs are at risk — even though pet stores are the most regulated group of pet providers,” the council said.

The American Society for the Prevention of Cruelty to Animals supported the bill and said the animals “generally live in overcrowded and unsanitary conditions” and “without adequate veterinary care, food, water or socialization.”

“While awareness of the puppy mill problem is growing, humane regulation at the state and federal level has been slower to evolve,” Matt Bershadker, the president of the society, said in the statement.

The law would take effect on Jan. 1, 2019. Violators face $500 in civil penalties.

More than 230 cities, towns, and counties across the country have passed ordinances to prevent the sale of cruelly bred animals at pet stores, including 36 local jurisdictions in California. But if signed, the bill would make California the first in the nation to regulate the sale of animals at the state level, the society said.

Matt Dababneh and Patrick O’Donnell, members of the State Assembly, introduced the bill to stop what a statement called “puppy mills, kitten factories and bunny bundlers,” or commercial breeders that mass produce the animals for sale.

A summary and fact sheet about the bill said it was meant to address “extremely minimal” federal standards, such as the requirement that a cage be only 6 inches larger than the animal it housed and cleaned just once a week.

There was also a financial consideration, according to the statement: California taxpayers spend about $250 million a year on animals in local shelters.

Breeders are licensed by the U.S. Department of Agriculture but some fall outside being regulated, said Daphna Nachminovitch, a senior vice president for People for the Ethical Treatment of Animals.

“There is no doubt that this will help cut down on the number of animals who go into animal shelters,” she said in a telephone interview. “Nothing in this bill stops people from purchasing an animal from a private breeder.”

California has a track record of animal protection measures.

In 2009, it became the first state to outlaw tail-docking of dairy cows, where the tail is partly amputated to ease milking. In 2008, voters passed Proposition 2, which gave hens, calves and pigs more room in their crates or cages.