After months of stalled negotiations, the union representing 6,500 workers who clean and protect some of the largest buildings and retail stores in the Twin Cities voted unanimously Saturday to authorize a strike over pay and sick leave.

Amid loud chants of “Si, se puede!” and “Strike! Strike! Strike!,” hundreds of workers with the Service Employees International Union (SEIU) Local 26 held up signs signaling their willingness to walk off the job if the cleaning companies and large contractors that employ them do not agree to an increase in hourly wages, more days of paid sick leave and stronger safety protections.

The vote represents a significant escalation in the union’s campaign to negotiate better contracts for the janitors and security officers, who work in some of the most prominent buildings in the Twin Cities, including the U.S. Bank Plaza, IDS Center the Ameriprise headquarters in Minneapolis and the Ecolab headquarters in St. Paul. The largest group negotiating contracts are janitors who work for commercial cleaning contractors, including ABM Janitorial Service and Marsden Building Maintenance. Approximately 500 are retail janitors who clean big-box stores for Best Buy, Target, Macy’s, Cub Foods and Lunds & Byerlys.

Iris Altamirano, president of SEIU Local 26 and the daughter of a janitor, said the union and the companies are still far apart on both wages and sick pay. For instance, the security officers are seeking pay raises of $2 an hour every year over the next four years, and the companies responded with an offer of 81 cents over the whole period, she said. The janitorial contractors have also rejected the union’s demand for at least 6 days of paid sick leave, 15-minute breaks and reduced workloads.

Full-time janitors in the SEIU local currently make about $16.40 an hour, and security officers make $13 to $16 an hour.

“To us, economics is broader than just wages. To us, economics is sick days. Economics is health care,” Altamirano said after the vote. “So when we think of economics, which are the top issues for our workers and their families, sick days are the biggest sticking point, and then wages.” She added of the contract talks, “The differences are still mighty.”

The SEIU local, which held the strike vote at its packed union hall in northeast Minneapolis, is known for its aggressive advocacy.

Four years ago, the janitors went on strike for 24 hours, setting up picket lines across the metro area as they asked for higher wages and better working conditions. They won significant improvements, including a 12.3% increase in wages over the four-year contract, as well as better access to health care coverage for part-time workers. Retail janitors with SEIU Local 26 also went on numerous strikes in the last five years and eventually won their first contract in 2016 — becoming the first union local in the nation to organize janitors at big-box retail stores.

“We are an invisible workforce and we should be respected for the hard work that we do,” Altamirano said.

A strike authorization vote does not mean that a strike will happen, but the bargaining teams for the union’s different sectors — commercial janitors, retail janitors and security officers — are now authorized to call a strike at any time if they are unable to secure what they consider to be a fair contract.