Thousands of unionized workers at DHL Express have voted overwhelmingly to authorize a strike if a new labor agreement is not reached by the end of March.

Members of the International Brotherhood of Teamsters approved the strike authorization by a 96% margin, giving union leadership the ability to call a work stoppage if negotiations with the logistics company fail to produce a new contract before the current agreement expires March 31.

The DHL Teamsters National Master Agreement covers thousands of workers across 26 local unions in 16 U.S. states. Union officials say negotiations must conclude with a national agreement and finalized local supplements before the deadline, and they have ruled out extending the current contract.

“DHL should be on notice that they need to start moving quickly to complete the supplements and present an acceptable contract offer,” said Bill Hamilton, director of the Teamsters Express Division, in a statement. “Our members will not work a day past the expiration of our current agreement.”

Union members say they want a new agreement that improves wages, working conditions, and benefits while maintaining existing protections.

Labor tensions previously escalated in 2023 when more than 1,100 Teamsters at DHL’s Cincinnati/Northern Kentucky air hub went on strike during a dispute over labor practices. DHL Express workers in Canada also went on strike last year, but came to terms on a new agreement after a three-week work stoppage.