SEIU Local 73, the collective bargaining unit that represents 230 Aviation Security Officers (ASOs) at O’Hare and Midway Airports, filed a lawsuit in Cook County Circuit Court alleging the city violated the terms of their labor contract. On Tuesday, members of the City Council’s Progressive Caucus plan to hold a press conference in support of the union and demand the city halt efforts to minimize their authority at the city’s two airports.

In the suit filed on July 20th, SEIU Local 73 argues that an ongoing effort by the Department of Aviation to strip ASOs of their law enforcement status by requiring the removal of “Police” monikers from their jackets and cars, as well as newly announced policies for emergency response that put the Chicago Police Department, not ASOs, as first responders to incidents at city airports violates the “Traditional Work” clause of their collective bargaining agreement with the city. That CBA was approved in 2011 and was extended in 2016 through the end of this year.