NORMAL - The work force at Mitsubishi Motors North America will get smaller next month. The company announced Friday that 105 union workers will leave the plant as part of a voluntary separation package the company offered in May.

"We have enough volunteers. We have plenty," said spokesman Dan Irvin, adding that workers will be chosen on the basis of seniority.

Ralph Timan, president of UAW Local 2488, which represents workers at the plant, declined comment Friday, referring all questions to the union's Detroit office.

Irvin said the workers will leave the company sometime in August, but was unsure of a specific date.

Under terms of the package, each will receive a lump sum payment of $85,000 and three months of medical benefits.

All are production workers, who assemble the company's vehicles. Union maintenance workers, who maintain the factory's equipment, were not eligible.

After the departure of the employees, the Normal plant will have 1,565 employees, including 1,261 union workers.

The employee reduction became necessary as the auto industry continues to struggle.

Last year, Mitsubishi's sales increased 9 percent, to 128,993 vehicles, bucking declines in the industry.

This year, though, sales have been more of a struggle.

Through June of this year, the company has sold 53,883 vehicles, down more than 23 percent from the 70,357 vehicles sold during the same time period in 2007.

Mitsubishi and the union are also in the midst of negotiations on a new contract. The current collective bargaining agreement expires Aug. 28.

The two sides have agreed not to discuss the progress of the negotiations while they are ongoing.