Striking Teamsters Threaten to Picket Tracy, Calif.-Area Stores, Warehouses.

Byline: Janet Adamy

Nov. 23--Workers at Safeway's Tracy warehouse plan to escalate the strike against their employer on Friday by starting to picket outside Safeway stores and other facilities.

Many of the 1,600 striking Teamsters have stood in front of Safeway stores to discourage customers from shopping there for more than a month, but they have not formally picketed the stores because of a technicality: they're striking against Summit Logistics -- the company that runs the warehouse and is their employer -- not Safeway. All sides had said it would not be legal to picket outside Safeway stores.

But on Wednesday, Teamsters Local 439 Vice President …