The terminals on the West Coast are always closed on July 5th to commemorate Bloody Thursday. On May 9, 1934, dockworkers in San Francisco went on strike, which eventually culminated in a riot on Thursday, July 5, 1934. Two strikers were killed in the riots. The strike and riots were the impetus for the formation of the International Longshore & Warehouse Union (ILWU), which is the union that covers the West Coast dockworkers to this day.
With July 5th being a Saturday, the holiday will be observed on Monday, July 7th.
Terminals in Oakland will be closed on both Friday, July 4th and Monday, July 7th to honor both Independence Day and Bloody Thursday respectively.