A union representing CenturyLink workers in 13 western states—including roughly 1,800 in Minnesota—said Monday that its members voted overwhelmingly to authorize a strike if a “fair contract” cannot be reached with their employer.

The current four-year contract expires Saturday night, and it affects 13,000 workers in Minnesota, the Dakotas, Iowa, Nebraska, and several other states extending to the west coast.

The Communications Workers of America said that more than 88 percent of its voting members approved the strike. The workers are former employees of Denver-based Qwest Communications, Inc., which in 2011 merged with Monroe, Louisiana-based CenturyLink.

Union spokesman Al Kogler said that negotiations began in mid-August, and one key sticking point is health care costs. Union members currently cover about 7 percent of their health care premiums, but CenturyLink has proposed boosting that share to 25 to 30 percent, a jump that “we think is way too much,” he said.

Of the roughly 1,800 Minnesota workers covered by the contract, about 1,600 are based in the Twin Cities, he said.

Kogler also said that the company has outsourced jobs to the Philippines and other locations, and “we’d like to bring some of that work back.” In addition, CenturyLink’s workers are held to stricter standards than contract workers, and the union would like to see the same standards applied across the board.

CenturyLink spokesman Mark Molzen told Twin Cities Business on Tuesday that the company “believes that the negotiating table is the best place to resolve issues and offers the best opportunity to come to a fair, equitable, and reasonable agreement.”

He said the company “looks forward to continuing the negotiation process,” adding that it is “critical to maintain competitive wages and benefits for employees while working to improve cost structure.”

The union is optimistic that a deal will be reached: “When deadline looms, this is when everyone gets serious,” Kogler said, adding that the bargaining teams are meeting “pretty much every day.”

But even if an agreement isn’t reached by the contract’s expiration, a strike is not inevitable, Kogler said. Both sides could agree to a contract extension, for example.

Union members also authorized a strike in 2008, during the last round of contract negotiations, but a strike did not occur. Rather, the previous contract was extended through the ratification of a new deal, according to Kogler.