A strike by hundreds of longshoremen who work the port of Baltimore's docks idled one of the region's big economic engines.

Launched early Wednesday morning, the strike shut down all of the port's public marine terminals, and its effects rippled out from the docks where ship crews waited for their vessels to be unloaded, to the truckers who haul cargo and cars from the port, to the warehouses that unload consumer goods.

It started after members of the International Longshoremen's Association Local 333 voted Tuesday night to reject a local contract with the Steamship Trade Association of Baltimore, which represent the port's employers of longshoremen.

A prolonged impasse could prompt shipping lines to divert cargo to nearby ports such as Norfolk, Va., and, port officials and others worried, diminish the industry's confidence in the port of Baltimore and its workforce, undercutting years of progress.

"Obviously it's not a good situation for the port, it's not a good situation for our port customers and it's obviously not a good situation for the men and women who work here," said Richard Scher, a spokesman for the Maryland Port Administration.

"It's my hope that the port returns to full operations as soon as possible," said Gov. Martin O'Malley.

Port-related businesses directly employ 15,000 Marylanders and the jobs of tens of thousands more are supported by the port, according to the Maryland Port Administration. The port is responsible for $3 billion a year in personal wages and salaries and more than $300 million a year in state and local taxes.

Crowds of union members stood outside entrances to Dundalk Marine Terminal on Wednesday morning holding signs reading, "No contract, no work," and "ILA Port of Baltimore on STRIKE!"

The port's 400-foot container cranes towered motionless in the distance at Seagirt Marine Terminal, where strikers also gathered. Only a few trucks passed through the normally busy gates.

John Furman, 28, of Essex, who grew up in South Baltimore and followed his father and grandfather as a longshoreman, said he would prefer to be working, but was striking to ensure he could provide for his family in coming years.

"It's a job," he said of his career for the past 11 years. "You don't want to see work leaving, you want to see work coming in. Then again you want something to work against. You want a good contract."

Members of Local 333, the port's largest ILA local, voted 517 to 25 Tuesday against the proposed local contract, said Riker McKenzie, president of Local 333. Following the vote, national ILA officials ordered the strike, he said.

Harold Daggett, the ILA's national president, declined on Wednesday to comment.

McKenzie declined to discuss specifics of the contract dispute, other than to say Steamship Trade officials "have been just flat-out refusing to engage" with union negotiators on a number of "housekeeping issues."

The port's three other ILA locals are honoring the picket lines even though they have agreed to local contracts.

The local contract covers workplace issues specific to Baltimore. The ILA agreed to a broader master agreement covering compensation and rules for container and vehicular shipments at all East Coast ports earlier this year. ILA locals in several cities still are negotiating local agreements, but Baltimore is the only port facing a strike.

O'Malley said port administrator Jim White is "on top of this," and that he understands that the two sides have asked a mediator to step in.

"We had been negotiating for quite some time and I think we have to get back to the table," said Michael Angelos, president of the Steamship Trade Association. "There's no reason not to continue that under good-faith bargaining efforts."

He declined to comment further on the impasse, except to say Local 333 is violating a "no-strike provision" in the master agreement governing port operations.

Helen Delich Bentley, a former Maryland congresswoman and an adviser to the port administration, said it is "most unfortunate" the local union broke that provision — a move she said may have long-term consequences for Baltimore.