Negotiators for a clerical union are working feverishly with management to avoid a strike at the Ports of Los Angeles and Long Beach.
The union, Local 63, is a division of the International Longshore and Warehouse Union, and represents 750 clerks who work at the ports.
The deadline for a strike was on Monday, but The Associated Press reported that negotiators from both sides worked past that deadline to try to reach an agreement.
Negotiations were still ongoing Tuesday, and neither side would predict a timetable for possible resolution.
Representatives of the 15,000-member Longshore and Warehouse Union said the union would honor picket lines if the clerks go on strike.
A strike could have devastating effects on shipping in the U.S. A similar strike in 2002 caused the ports to shut down for several days, and shipping took months to get back to normal.