SAN FRANCISCO (AP) - A frail labor peace between shipping lines and West Coast longshoreman collapsed Sunday when workers were ordered off their jobs indefinitely.

The Pacific Maritime Association, which represents the shipping lines, said it would bar workers from the docks until the union agrees to extend a lapsed contract while talks toward a new agreement continue.

West Coast ports handled more than 0 billion in cargo over the past year. Continued labor unrest could cost the U.S. economy an estimated billion a day.

"They're just doing whatever they're doing," said Steve Stallone, a spokesman for the International Longshore and Warehouse Union.

Association president Joseph Miniace called Sunday's action a "defensive shutdown" that came less than 12 hours after longshoremen returned to the docks at the 29 major Pacific ports.

Shipping lines imposed a lockout Friday immediately after talks broke down. That lockout was lifted, then reimposed after the association accused the union of understaffing operations and dispatching unskilled workers.

Shipping lines said productivity fell "off the cliff" Sunday.

"It's like a plumber showing up to roof your house," said Bill Niland, a manager for the association's San Francisco area. "Aside from the production issue, there are certainly safety issues."

Added Miniace: "I will not pay workers to strike."

In the 36 hours the docks were closed, about 30 ships had to moor outside berths at ports in Los Angeles, Oakland, and Seattle and Tacoma, Wash.

That meant hundreds of millions of dollars worth of Pacific Rim trade wasn't entering the U.S. distribution chain — a blow to importers who are scrambling to secure goods for the holiday season. At the same time, exporters feared a prolonged disruption would see their goods stuck on the docks.

Miniace appealed for a federal mediator.

A message left Sunday evening with the U.S. Labor Department ( news - web sites) was not immediately returned. The union has accused the Bush administration of meddling in talks, which began in May.

On Sunday, it was clear that the association's first lockout — what it termed a "cooling-off period" — hadn't brought peace to the waterfront.

The union's San Francisco chapter, historically one of the most militant on the coast, told workers to report to a dispatch hall for random assignment.

That meant, for example, that experienced crane operators chose other jobs, and left their less experienced co-workers to operate the cranes.

At the Maersk terminal in Oakland, no operators took jobs on three cranes to load the last few containers on a ship that was otherwise ready to steam out.

"They wanted us to come back like we were going to be good little puppy dogs," said Richard Mead, president of the San Francisco chapter. "It doesn't work like that on the waterfront."

Earlier in the bargaining, there were signs of progress over benefits and pensions packages. But the talks began deteriorating during the summer, and they crumbled this week over the question of how to implement new technology on the waterfront.

Contract talks between the two sides crumbled this week over the question of how to implement new technology on the waterfront. The union said it could accept short-term job losses from increased efficiency but wanted guarantees that positions created by computer tracking systems would be union-covered.