Police departments obtain the equipment through a federal program that provides them with military surplus items for free. The Los Angeles and San Diego school districts made headlines after their police departments received armored vehicles through the program. LA also acquired rifles and grenade launchers.
Democratic Senator Bill Monning has introduced legislation that would require school boards to approve the acquisitions. He says his measure does not ban the equipment.
"My bill allows for a school district to make the case why acquiring certain weaponry may be important for the safety and security of that school," Monning says.
Michael Dorn is a former school police chief who now runs Safe Havens International, a non-profit focused on campus safety. He says he understands the need for oversight but there are reasons departments might not disclose which weapons they have.
"We do know that in previous terrorist attack here in the US and abroad for school targets they do often try to scope out and find out what they would be up against," he says.
Dorn says school police departments may use the military equipment as a deterrent. He says larger guns often prevent attackers from beginning or continuing an assault.
The LA Unified department has since returned the grenade launchers. San Diego has returned its armored vehicle.