LONGVIEW, Wash. (AP) — Union workers at Georgia-Pacific's Wauna mill in northwest Oregon have given negotiators strike authorization as contract talks with the company have bogged down, a union representative said Monday.

The 900 members of the United Steelworkers local 1097 have been working under a contract that expired in April 2010, said Gaylan Prescott, the union's staff representative. The union voted down a company contract offer in January, and the next contract talks are scheduled May 24 with a federal mediator, he said.

Prescott said last week's vote "overwhelmingly" favored strike authorization, with nearly all members voting. He declined to give exact numbers. Union negotiators are required to give a 10-day notice before calling a strike, but Prescott said they plan to continue talks.

A strike "is certainly a possibility. But we're hopeful we can avoid that," he said.

Health care benefits are the major sticking point, Prescott said. Wauna union workers currently pay about 25 percent of their insurance premiums through Kaiser Permanente. The company wants to switch health insurance through United Healthcare. The plan would cost them more to insure family members and require them to find new doctors, Prescott said.

For employees with multiple children, "it could be a significant increase in what you're paying," Prescott said.

The Wauna mill, located near Westport in Clatsop, manufactures tissue, paper towels and toilet paper. Georgia-Pacific operates 20 mills nationwide producing consumer products, pulp and containerboard.

Kristi Ward, a Georgia-Pacific spokeswoman, said the company is offering workers a 6 percent wage increasing over the four-year contract and a boost in pension benefits. The average union Wauna worker makes about $70,000 per year, she said.

Over the past four years, the company has negotiated the same medical benefits with United Healthcare to cut costs at most of its other paper mills nationwide, she said.

"The long-term success of the Wauna Mill is important to us and so are our employees. It's always been our goal to participate in an open dialogue with Local 1097 throughout this whole process," Ward said.

Wauna papermakers last voted for strike authorization in 1995, when they were represented by the United Paperworkers International Union local 1097 and the mill was owned by James River Corp. The two sides ended up avoiding a strike and signed a five-year contract.

The mill last had a strike in the mid-1970s, Prescott said.