The union representing about 1,600 nurses at Washington Hospital Center has voted to hold a one-day strike in early March to protest the lack of progress in a labor dispute at the area’s biggest hospital, a spokesman for National Nurses United union said Wednesday.

Ken Zinn said no date for the strike has been set. The union is required to give management a 10-day notice. This is the second time the union has taken such a vote. In November, the union voted to hold a one-day strike the day before Thanksgiving but canceled it after the two sides agreed to resume negotiations for 90 days without threat of a strike.

Both sides agreed that those talks have yielded little movement, although they disagree on the outstanding issues. The two sides have been at odds over wages, benefits, staffing and patient safety.

“We haven’t made significant progress, and the nurses are angry and frustrated,” Zinn said. He declined to give the vote tally but said “just under 90 percent” of those voting backed the decision.

The hospital, in a statement, said it couldn’t verify the accuracy of the vote. “Although the union talks of promoting patient safety, we do not believe that asking nurses to leave patients at the bedside actually promotes that safety,” the statement said.

Nevertheless, if the union calls a strike, the hospital has a contingency plan and will remain open on a full schedule, officials said.

Hospital officials have been bracing for a possible job action since the one-year contract with the nurses expired and talks broke down in the summer. In October, management imposed a wage plan that provided wage increases but also cut the shift differential for evening, night and weekend work.

The union has accused the hospital of unsafe staffing levels in dozens of incidents, but managers said they have been unable to verify them.

The union cited an internal survey of hospital employees conducted by the hospital last year that showed a significant percentage of employees think that the hospital is lacking in patient safety.

In the survey, Washington Hospital Center had the worst results of eight hospitals owned and operated by Columbia-based MedStar Health. Of 12 indicators of “patient safety culture” identified in the federally designed survey, not one was ranked as a “strength” by the 4,400 participating employees; all fell below the national average. Four indicators, including staffing, teamwork across units and responses to errors, were considered weak. By comparison, Georgetown University Hospital and Montgomery General Hospital, also part of MedStar, each had one “strength” score, for teamwork within units.

Janis Orlowski, chief medical officer at Washington Hospital Center, said managers used the survey to “get a base line of employee perception about patient safety.” The survey was taken last year at a time when the labor dispute was particularly contentious, “so we knew we were going to be low,” she said. It was the first time the hospital participated in the survey, she said.

Hospital managers are using the survey results to focus on the weak areas and using them to improve patient safety, she said.