Members of the Teamsters union have authorized a strike against Costco on February 1 unless they reach a deal with the warehouse retailer before the current contract expires on January 31.

The union said 18,000 Costco workers are set to go on strike at 56 of the company’s warehouse stores spread across five states after 85% of members voted to authorize a strike. In addition to disagreements on wages and benefits, the union said Costco had rejected union proposals dealing with seniority pay, paid family leave, bereavement policies, sick time, and safeguards against surveillance.

The company did not respond to a request for comment on the strike vote.

The Teamsters covered by the Costco national contract make up 8% of the 219,000 US employees that the company has at 616 US stores, according to company filings. But a strike by that many workers it represents a major strike for a US retailer, which is overwhelmingly nonunion. Labor Department statistics show less than 5% of retail workers are represented by unions. Most are in the grocery store sector.

The Teamsters staged a strike at Amazon just before Christmas, but unlike the situation at Costco, Amazon does not recognize the union as representing any of its workers and has refused to negotiate with the Teamsters, let alone reach a contract. It doesn’t even recognize that many of the strikers, who are drivers for third-party delivery services who have exclusive contracts with the online retailer, are its employees. The workers at Amazon who went on strike returned to work the day after Christmas.

The strike authorization vote does not mean there will be a strike. Strike authorization votes are a common tactic used by unions ahead of a contract expiration. And the overwhelming majority of workers generally authorize a strike in those votes. In June 2023 97% of Teamsters voted to authorize a strike at UPS, the union’s largest employer. But two weeks before that strike deadline the union reached a labor deal that averted at strike at UPS.