With their contract expiring on Friday, hundreds of janitors with the 32BJ SEIU said they’re ready to strike if a new contract isn’t signed by then.

Negotiations for a new, multi-year contract began last month between the union and the Maintenance Contractors Association of New England, which contracts with over 13,000 janitors in the state.

The workers clean about 2,000 buildings in the Boston area, including the John Hancock, Prudential Tower, Vertex and Biogen buildings, Eugenio Villasante, spokesman for the union, told the Boston Globe.

The janitors also work in area schools, such as Northeastern, Bentley, Wentworth, Simmons, and New England Conservatory, as well as MBTA buildings, he said.

“The key pillars of the economy here—finance, tech, health care, insurance, transportation (MBTA), and education—wouldn’t have janitors, starting in October,” Villasante told the paper.

The union said that major issues included “fair wage increases” and “protections against unreasonable workloads,” according to a statement published on its website.

“Four years ago when cleaners negotiated their last contract, the country was in a recession,” the statement reads. “Since that time, vacancy rates in Boston’s office buildings have dropped almost back to their pre-recession levels while rents have climbed even higher than they were before the recession.”

A spokesperson for the contractors association told the paper that “real progress was made on economic issues like wages and health care,” and that, “as a result, the [association] believes today’s union strike vote is unnecessary.”