CHICAGO — Chicago’s 24-below-zero wind chills did not halt a protest Monday to advocate for a $15-an-hour minimum wage for airport workers.

Organized by the Service Employees International Union Local 1, the protest by about three dozen people outside United Airlines’ headquarters was among nine civil disobedience actions in cities across the United States on Martin Luther King Jr. Day.

The SEIU, which is also behind the Fight for $15 campaign for fast-food workers, is pushing for higher pay, benefits and job protections for airport janitors, cabin cleaners, wheelchair agents, security officers and baggage handlers.

Baggage handler Raquel Brito, 20, who works at Chicago’s O’Hare International Airport, stood before a bank of microphones and through chattering teeth told of the challenge of paying bills and putting food on the table.

“We are tired of struggling to get by,” said Brito, who makes $11 an hour and works in the United terminal as a contractor for Prospect Airport Services. She was previously a wheelchair assistant, which paid $6.75 an hour plus any tips passengers gave. Brito said her aunt and grandmother also work at O’Hare, cleaning the airplane cabins and airport terminals.

Brito said she injured her back several months ago while pushing a passenger and, because she doesn’t get any health benefits, had to pay most of her health care costs herself. Brito still spends $250 monthly for physical therapy for her injury, including transportation expenses, union spokesperson Izabela Miltko said.

Brito was among about 14 airport workers and supporters who lined up, arms hooked, in the middle of a downtown street for about three minutes in the cold before police started arresting them and leading them away.