SACRAMENTO, Calif. — California became the fifth state to prohibit openly carrying handguns in public after Gov. Jerry Brown announced today that he had signed the ban into law amid heavy opposition from gun enthusiasts.

The new law makes it a misdemeanor to carry an exposed and unloaded gun in public or in vehicles, with violators facing up to a year in prison or a potential fine of $1,000 when the law takes effect on Jan 1.

The bill exempts hunting and shooting events and does not apply to those who are given permits to carry a concealed weapon by law enforcement authorities.

Bill sponsor Anthony Portantino said the bill is an opportunity to prevent tragedy before it happens.

“It’s not if somebody is going be shot, it’s when somebody is going to be shot,” he said. “We have the opportunity to avoid that, and that’s why this is so critical.”

He said law enforcement officials have been concerned about the proliferation of guns in public and the tense situations that arise when someone sees another person carrying a firearm in public. He said the encounters can escalate quickly because others don’t know whether the gun is loaded or unloaded.

“Main Street California is not the Old West, and you don’t need a gun to buy a cheeseburger,” Portantino said.

Top California law enforcement groups, including the California Police Chiefs Association and the Los Angeles Sheriff’s Department, supported the legislation.