General Motors Corp. (GM) will close its van assembly plant in Baltimore in 2005, affecting about 1,100 active workers, the president of the United Auto Workers (search) union local said on Thursday.

"We're slated for closure for 2005," UAW Local 239 President Walter Plummer told Reuters. A GM spokesman declined to comment.

GM has not scheduled any new vehicle production in the plant beyond summer 2005, the spokesman said.

Some of the affected workers could transfer to GM's new Allison Transmission plant in Baltimore, said Mike Robinet of industry consultant CSM Worldwide.

The closure is part of the tentative agreement on a four-year contract reached Thursday between the UAW and GM. UAW contracts with the Chrysler arm of DaimlerChrysler AG (DCX) and Ford Motor Co. (F) have also included planned plant closures and job cuts in exchange for moderate increases in wages and pension benefits.

The Baltimore facility builds the Chevrolet Astro (search) and the GMC Safari (search) mid-size vans, which were introduced in 1984 and have not been re-engineered since then. Automakers have focused on more driver-friendly front-wheel drive vans.

GM's Baltimore and Linden, New Jersey plants, both built in the 1930s, have long been viewed for closing as the automaker fights falling market share and mounting health care and pension costs.

"Producing vehicles on the right (east) coast is getting to be more and more difficult with logistics in terms of bringing components and vehicles from that destination to the Midwest and the South," Robinet said.

Union officials at the N.J. plant said Thursday they had heard it would remain open at least through 2007, two years longer than expected.

"It's great news for us," said Guy Messina, president of the UAW Local 595, which represents about 1,200 active workers there.

GM previously said it had not approved any new vehicles at the plant through 2007. However, Messina said he heard from UAW officials in Detroit that GM would protect jobs in New Jersey through the life of the four-year contract. He said he thought GM would manufacture a new vehicle at the plant after 2005 but had no other details.

"We received news that we've been extended through 2007," Messina said."

The N.J plant currently builds the Chevrolet S-10 (search) and GMC Sonoma (search) mid-size pickup trucks and the Chevrolet Blazer (search) mid-size sport utility vehicle.

But those vehicles are becoming obsolete. GM already builds a newer version of the Blazer, called the TrailBlazer, and is scheduled to begin production of new mid-size pickup trucks in Shreveport, Louisiana, in October.