Tacoma’s public schools will be closed for a fourth day Tuesday as an ongoing dispute over teacher pay creates the state’s largest work stoppage of educators.

The Tacoma Education Association, which represents teachers, declined the district’s request for binding arbitration, the district wrote in an email update Monday night. “Both sides remain far apart at the bargaining table,” the district said.

Over the weekend, the school district filed a request for fact-finding and arbitration with the state's Public Employment Relations Commission, according to a statement posted on the district's website. The commission's recommendations would be nonbinding. Dan Voelpel, a spokesman for Tacoma Public Schools, said the district wants to "operate from the same set of facts" in its talks with the teachers.

"We had just finished nine days of mediation with not much progress," Voelpel said on Monday. The teachers union "is still demanding high-double-digit pay increases, but we are hoping to bring an end to this as soon as possible. We think we need to clearly demonstrate it's not a lack of willingness to pay, but a lack of ability, as we did not receive the windfall of cash that other districts had."

Across Washington, teacher contract negotiations have been particularly fraught after lawmakers this year injected about $1 billion into the state’s K-12 budget to pay for educator salaries. The infusion of cash prompted the Washington state Supreme Court to close the decadelong school-finance case known as McCleary. But the extra money also automatically opened teacher contracts for renegotiation in virtually all of the state’s 295 school districts.

Angel Morton, president of the Tacoma Education Association, the teachers union, called the district's fact-finding and arbitration request a "stall tactic."

"We lost two whole days of negotiations over the weekend," Morton said on Monday. "It is just a way to keep schools closed, and they are harming their own students. My teachers are not going back if they don't have a competitive wage because they are holding out for the money. We are not being greedy; we are just asking for what’s ours."

Tacoma's public school district is the fourth-biggest in Washington, with an enrollment of more than 29,000 students, or 2.6 percent of the state's total, according to official data. When combined with ongoing teacher strikes in Battle Ground, Centralia and Tumwater, the holdouts in the four districts have impacted more than 53,000 students, just under half of whom come from low-income households.

The Centralia School District struck a tentative agreement with educators Monday night, according to the Centralia Education Association. Centralia schools will remain closed Tuesday. Union members will vote on the tentative agreement Tuesday at 8 a.m., said Washington Education Association spokesman Rich Wood. Students in first through 12th grades will return to school Wednesday and kindergarten will start Monday, according to the district.

Voelpel said the state provided his district with an extra $50 million this year, while cutting $46 million from a levy that the district relied on to fund its budget last year, resulting in a near-wash.

Mike Sellars, the executive director of the state commission that's acting as the mediator, said requests from school districts are "not commonly used procedure." Similar fact-finding missions were conducted in 2016 at the Granger School District, and in 2009 in Marysville, he said.

The commission will issue a nonbinding set of recommendations, "but the parties will still need to work together to reach an agreement," Sellars said. "We have committed to doing everything we can on our end to turn it around as quickly as possible."

Seattle Times staff reporters Neal Morton and Heidi Groover contributed to this story.