US lawmakers on Thursday proposed a ban on the private possession and breeding of big cats, saying that roadside zoos found around the country were inhumane and put humans at risk.

Wild animal ownership made headlines in 2011 when a suicidal man near Zanesville, Ohio, flung open the doors of his farm before shooting himself. Dozens of lions, tigers and other animals ran amok until police shot them dead.

Representatives Buck McKeon and Loretta Sanchez, a Republican and Democrat respectively from California, introduced a bill to prohibit private possession and breeding of big cats, replacing widely inconsistent state laws.

"No matter how many times people try, big cats such as lions, tigers and cheetahs are impossible to domesticate for personal possession," McKeon said in a statement.

The law would exempt certified zoos, wildlife sanctuaries and -- in a change from a proposal that failed during the last session of Congress -- some circuses, which have sought safeguards for the industry.

Under the revised proposal, traveling circuses will be allowed to own and breed big cats if they do not allow visitors to handle the animals, and under other conditions.

The International Fund for Animal Welfare, which encouraged the bill, said that 10,000 to 20,000 big cats are living in the United States as pets or for profit. The advocacy group said that more than 200 humans have been mauled, with at least 22 dead, in incidents since 1997.

Tracy Coppola, the campaigns officer for the fund, said that the market was fueled by demand for cubs who are seen as cute for photo opportunities. Once they grow up, the cats are sent off as surplus.

"When I first learned about this type of industry, I thought that was very weird and discreet. But the more you look into it, the more you realize that this is a really lucrative industry," she said.