Janitors across the Twin Cities metro area walked off the job and took to the streets Wednesday in the midst of tense negotiations with cleaning companies over wages and working conditions.

The 24-hour strike was the first by subcontracted union janitors in the Twin Cities in decades, according to Local 26 of the Service Employees International Union, which represents roughly 4,000 janitors in the metropolitan area.

Picket lines popped up at office buildings across the metro throughout the day and coalesced in downtown Minneapolis, when hundreds rallied at U.S. Bank Plaza as night fell and a surge of white-collar workers left their offices for home.

The protesters blocked a couple of downtown streets for about 10 minutes during their rally. No one was arrested.

The gathering erupted in cheers when Javier Morillo, the president of Local 26, pointed up at Capella Tower and said that today, “the bosses are cleaning the bathrooms.”

Members of Local 26 work for cleaning companies who in turn have contracts with office building owners. Most of them work in downtown Minneapolis and St. Paul, but some are in office buildings scattered around the seven-county metro area.

The key cleaning companies negotiating with the janitors are ABM Janitorial Services, Marsden Building Maintenance, ABLE Building Maintenance and Harvard Maintenance.

Full-time janitors make $14.62 an hour; part-timers make $11 to $13 an hour. The union has asked for immediate wage increases of $1 an hour across the board, and a total across-the-board increase of $3 per hour by the start of 2018. SEIU negotiators have also proposed raising part-timers’ hourly pay to $15 an hour by the end of a new three-year contract, and giving workers more sick days.

The companies offered in January to raise all full-time workers’ pay above $15 per hour over three years — but not part-time employees.

Negotiations began in November, and both sides say the other has not moved from its original proposal.

Union members voted Jan. 23 to walk off the job, and made good on their promise Wednesday.

“The employees working under this agreement receive a wage and benefits package that is well above the Minneapolis-St. Paul average,” said John Nesse, a lawyer and spokesman for the cleaning companies. “The employers respect the union’s right to strike. At the same time, we already have a bargaining session scheduled for February 22nd at the union’s request, and we look forward to getting back to negotiations.”

Striking janitors protested at the Minneapolis-St. Paul International Airport, Medtronic offices in Fridley, UnitedHealth offices in Eden Prairie and Best Buy headquarters in Richfield. Groups picketed at the Securian Building in St. Paul and at three buildings in downtown Minneapolis: the Ameriprise headquarters, the IDS Center and the Baker Center.

In front of Ameriprise, Elia Starkweather led about 70 protesters in chants as they walked in a circle next to the bus stops where commuters congregated at the end of the day.

She and one other janitor clean two floors of cubicles and 14 bathrooms each night. She has been a janitor for five years, and her family doesn’t have the money for a second car, so her husband drives her to work every day from their home in Hopkins.

She believes the cleaning companies will get the message from Wednesday’s protest, but added that she is willing to strike for longer.

“They are going to see the work we do every night,” she said. “We are going to do whatever we have to do. Even if it’s a month, I’m going to be right here.”

At the rally after dark, workers gathered under outdoor heaters set up next to U.S. Bank Plaza and stood in line at a portable restroom set up along 6th Street. Morillo, the president of Local 26, said the key issue for workers, more important even than wages, is workload.

In the past, when they have received a pay increase, janitors say their workload has increased. The union wants an agreed-upon standard for how much work a janitor must do and a better way to resolve disputes.

“It is the single most important issue for workers,” he said.

The protest attracted the attention of Hillary Clinton’s presidential campaign. “To raise incomes, we need to support unions and a living wage. I stand with working Minnesotans today,” Clinton said on her Twitter account.

In Eden Prairie, there was a miscommunication and janitors who clean didn’t show up for a midafternoon protest.

Two vans full of airport janitors rolled up, however, and everyone piled onto the quiet parking lot of a strip mall. Signs were passed out and about 25 people marched up to the beige and glass towers off Hwy. 212, chanting and bobbing signs that said, in Spanish, “We clean for the rich. We are on strike.”

Hawa Hussein, a mother of seven who has cleaned concourses and bathrooms at the airport for 10 years, said Wednesday was the first time she’s participated in a strike.

“Children need clothes,” she said. “I need better benefits, more money, sick days.”

The airport janitors, who are employees of ABM Janitorial, said none of their colleagues worked Wednesday, and they assumed managers were cleaning bathrooms and emptying garbage.

Asked whether she was worried about striking, Hussein said, “I’m not scared.”

One of her colleagues at the airport, Yusuf Abdi, jumped in and said there is no reason to fear the cleaning companies.

“One person strikes, they can do something, but all of us?” Abdi, who’s worked at the airport for two years, said. “They can do nothing.”