The Ports of Los Angeles and Long Beach were back in operation Saturday after a worker shortage shut down the largest U.S. port complex for the better part of two days.

The shortage came following protracted labor negotiations between the West Coast dockworkers union and the industry group representing shippers. Both parties are negotiating a new contract with wages and the role of automation as top priorities.

The old contract with the International Longshore and Warehouse Union expires July 1. Four terminals at the twin ports of Los Angeles and Long Beach shut down during the labor shortage. Workers returned to the docks Friday afternoon.

The Pacific Maritime Association, representing the employers of dockworkers on the U.S. West Coast, claimed that problems stemmed from a local union withholding labor for the evening shift on Thursday night.

Photo courtesy Port of Los Angeles