KANSAS CITY, KAN. ? General Motors on Monday kicked off production of its new Chevrolet Malibu after spending six months and $500 million preparing its plant and workers in Kansas City, Kan., to build the midsize sedans.

The Fairfax plant, which employs about 2,500 people, had made the Pontiac Grand Prix. It shut down in February and has been undergoing an extensive retooling to build the new cars — a new Malibu and a hatchback called the Malibu Maxx. Workers, who have been back since mid-July to prepare for the launch, began making cars for customers Monday.

“This is our job security right here,” plant manager Paul Marr said at Monday’s celebration of the start of production.

What used to be the Malibu has been renamed the Chevy Classic, and is built in Lansing, Mich.

GM, the nation’s largest automaker, plans to make 250,000 Malibus each year at the Fairfax plant — the only place where they will be made. The 2004 models should begin arriving at dealerships later this month.

Gov. Kathleen Sebelius and GM North American President Gary Cowger, a native of Kansas City, Kan., drove production car No. 1 onto the plant floor.

“I’m committed not only as governor to this great project, but I’m committed as a driver,” said Sebelius, who plans to lease one of the cars. “I can’t wait for my car.”

Cowger said the launch was critical to GM’s goal to make the company a leader in midsize cars. GM made the investment in the Fairfax plant even as the auto industry faced sluggish sales and rising competition.

Cowger said the community and Fairfax workers should consider it a compliment that GM picked the Kansas City, Kan., plant for the new Malibu.

“We’re counting on you. All of General Motors is counting on you,” he said.

Kansas Gov. Kathleen Sebelius and General Motors North American President Gary Cowger talk about the new Chevrolet Malibu during the launch of the new, midsize sedan at GM's Fairfax assembly plant in Kansas City, Kan. GM officials hope to produce 250,000 Malibus a year after spending 00 million preparing the plant to build the car.