Article Photos: Radar center problem snarls Chicago air traffic 1/4

Police and firefighters are seen at the Chicago Terminal Radar Approach Control, or TRACON, center in Elgin, Ill., Tuesday, May 13, 2014, after smoke at the radar facility forced a ground stop to all incoming and outgoing flights at both of Chicago's airports. The Federal Aviation Administration says all its personnel at the facility were evacuated. (AP Photo/Daily Herald, Brian Hill)  MANDATORY CREDIT, MAGS OUT