Potlatch Corp. woodworkers in Lewiston are poised for the picket lines.

Union leaders say an official strike comes after negotiators on Tuesday failed to resolve differences with the timber company over salaries and pension benefits.

The strike involves 265 employees at the company’s sawmill and power boiler, though union officials have not said when the workers will take to the picket lines.

It marks the first strike at the mill since 1948.