Unionized Hilton workers in Chicago will vote this week on whether to authorize a strike, making them the third group of workers in nine months to hold such a vote in the wake of unsettled contract negotiations between Chicago hotels and the union.

The vote authorizes the union’s negotiating committee to call a strike if it is deemed necessary. In October, Chicago hotel workers voted to authorize a strike at five downtown Starwood hotels affecting 1,500 workers, followed by a vote last month covering 1,600 Hyatt hotel workers, who also agreed to authorize a strike. So far, none have called for a strike.

According to Unite Here Local 1, workers at Blackstone Group-owned Hilton have seen staff cuts, reduced hours and excessive injury rates. Among those voting over the next two days to authorize a possible strike are workers from the Drake, Palmer House, Chicago Hilton and Hilton O’Hare. The results of the vote — which covers 1,800 hotel workers — will be announced Thursday evening.

Union contracts covering 6,500 workers at 31 hotels in downtown Chicago expired Aug. 31, and the two sides have been unable to reach a settlement, according to Unite Here Local 1.