Story highlights Union representing Chicago aviation officers asks mayor for guns

The request follows a CNN investigation

Hundreds of aviation officers are instructed to run and hide if there is an attack

(CNN) The union representing aviation police officers at Chicago's two airports is asking Mayor Rahm Emanuel to shore up security by allowing officers to carry guns.

The request follows a CNN investigation that found that hundreds of aviation police officers are not armed and have been told to "run and hide" in the event of an active shooter.

A longstanding policy prohibits those aviation police officers from carrying a gun even though they are certified law enforcement officers; about 300 of them work along with armed Chicago police, which is the primary law enforcement agency at both airports.

CNN Investigations Email your story ideas and tips to CNNtips@cnn.com.

"The safety of the flying public that utilize the Midway and/or O'Hare airports, and the APOs (aviation police officers) who are an integral part of the security of these airports is at high risk for compromise," according to a January 4 letter to Emanuel from Matt Brandon, secretary-treasurer of Local 73 of the Service Employees International Union.

The "run and hide" training given to aviation police "is contrary to everything... taught in the Chicago Police Academy," Brandon wrote.

Read More