The contract that covers dockworkers who handle hundreds of billions of dollars of imports and exports at 29 West Coast ports is set to expire.
The union representing nearly 20,000 dockworkers has been negotiating with shipping lines and port terminal operators, but no deal is likely before their contract ends June 30.
Past negotiations have not always gone smoothly, though both sides say they will negotiate beyond the deadline without disruptions to trade.
Jittery retailers aren't taking any chances.
Stung by a lockout in 2002 that shuttered the ports for 10 days, some importers have shifted to ports on the Gulf and East Coasts, or they've brought goods in early for back-to-school and holiday shopping.