FACTBOX: GM's Opel sites and staff in Europe

FRANKFURT (Reuters) - Germany's state and federal governments plan to decide by Christmas whether to extend a guarantee of 1 billion euros ($1.26 billion) to Opel, should its Detroit-based parent General Motors file for Chapter 11 bankruptcy protection.

GM Europe has ruled out a collapse of the German carmaker, which traces its roots back to 1899 and has been part of GM since 1929, longer than rival Volkswagen has existed.

Below are the main factories building Opel cars in Europe which may benefit from mooted financial guarantees. Adam Opel GmbH is an integral part of the U.S. carmaker's GM Europe subsidiary, which also produces vehicles under the Cadillac, Saab and Chevrolet brands.

RUESSELSHEIM, Germany: About 16,000 employees assemble up to 270,000 vehicles a year at Adam Opel GmbH's headquarters. The factory makes the Vectra and Signum models as well as the new Insignia model, which is due to hit showrooms later this week. The site also houses technical development.

BOCHUM, Germany: Three factories with a staff of 5,300 produce about 240,000 Zafira compact vans and medium-sized Astra passenger cars per year in Germany's traditional coal-mining district.

EISENACH, Germany: About 1,800 workers assemble Opel's compact car Corsa at the plant which was inaugurated in 1992 as a hallmark project to revive eastern Germany's decrepit industrial structure.

KAISERSLAUTERN, Germany: About 2,300 employees manufacture engines and components.

ZARAGOZA, Spain: The factory has an output of about 490,000 units per year, mainly Corsas and Meriva minivans.

GLIWICE, Poland: The site has an annual output of about 190,000 vehicles, mainly Agila sub-compact cars, Astras and Zafiras.

ANTWERP, Belgium: The facility has an annual output of about 200,000 Astras.

ELLESMERE PORT, Britain: The site assembles about 130,000 Astras under the Vauxhall hallmark, the British version of the Opel brand.

ST. PETERSBURG, Russia: GM Europe inaugurated the site November 7 and plans to produce 170,000 units under the Opel and Chevrolet brands for the Russian market per year.

(Reporting by Ludwig Burger; editing by Simon Jessop)