General Motors' 68-year-old Baltimore, Maryland, assembly plant is the only major GM factory earmarked for closing as part of the car maker's tentative new agreement with the United Auto Workers, union local presidents were told by UAW bosses, Associated Press (AP) reported.

According to AP, the local officers were in Detroit on Sunday to hear highlights of the proposed four-year labour pacts announced last Thursday with GM, the last of the 'Big Three' United States car makers to reach an agreement, and with supplier Delphi Corporation.

According to a UAW-produced document prepared for the officers and obtained by The Associated Press, GM has identified three facilities for closing: the Baltimore plant, which has about 1,100 UAW workers; a powertrain plant in Saginaw, Michigan, with 378 employees; and the Argonaut Building, an ageing office structure in Detroit.

AP said that GM builds the Chevrolet Astro and GMC Safari vans in Baltimore and that the plant's future was uncertain because GM had no work assigned to it beyond 2005 - when it is now scheduled to close.

During negotiations, Delphi, which was spun off from GM in 1999, proposed consolidating six facilities, the document obtained by AP says - the supplier proposed merging two plants in Flint, Michigan; its Tuscaloosa, Alabama, plant into an operation in Lockport, New York; and an Olathe, Kansas, facility into Fitzgerald, Georgia.

"The UAW resisted this proposal and Delphi withdrew it," the UAW document says, according to Associated Press, adding: "Nevertheless, the company notified the union that it intends to raise the issue of potential consolidation of these facilities during the term of the 2003 agreement."

Company representatives have declined to discuss details of the proposed pacts, AP said, noting that the proposed four-year contracts between the UAW and GM, Ford, Chrysler, Delphi and Visteon still require ratification by rank-and-file members, a process expected to take place in the next week.