California Gov. Jerry Brown signed a bill that says that teachers cannot shoot back if they come under attack at school.

The bill, AB 424, was introduced by Assemblyman Kevin McCarty (D-Sacramento).

California state law already prohibited civilians who are not school workers from bringing firearms onto campuses, but a change in the law last year gave school district superintendents power to decide if employees could bring concealed weapons onto campuses, reported the LA Times.

McCarty introduced the bill after five California school districts chose to allow teachers and/or staff with concealed carry permits to be armed on campus to defend themselves and their students. The five districts were Kern High School District, Kingsburg Joint Union High School District, Folsom Cordova Unified School District, Anderson Union High School District, and Palo Cedro’s North Cow Creek School District.

The measure, AB 424, was opposed by groups advocating for gun owners including the National Rifle Assn. and the Firearms Policy Coalition, said the LA Times, which reported that there have been no shootings involving California school employees who brought guns to campuses.

Critics of the new measure said it will leave school staffers helpless to stop an armed intruder on school grounds.

“You’re taking away the ability to protect our children,” said Republican Assemblyman Devon Mathis of Visalia. “People with concealed carry weapons are trained and schools are already soft targets.”