Chicago’s O’Hare and Midway airports have nearly 300 sworn aviation police officers wearing uniforms and badges. One thing they don’t have – guns. A CNN investigation revealed that these sworn, unarmed officers have been instructed to run and hide in the case of an active shooter.

CNN surveyed other major airports and found that most use a mix of armed police officers and unarmed security guards.

While Chicago airports do have more than 200 armed officers from the Chicago Police Department, the decision to leave hundreds of sworn law enforcement officers without guns has puzzled some experts and union leaders.