PEORIA, Ill. (AP) - A group of former and current workers is accusing Caterpillar Inc. of using a performance evaluation system introduced last year to force older employees from the company.

Twenty-nine current and former Caterpillar workers have filed a lawsuit claiming the process was "misused by supervisors to discriminate against and to hasten the departure of older employees" because of their age.

A Caterpillar spokeswoman said Tuesday the evaluations were based solely on performance.

The older workers received good evaluations until Caterpillar introduced the new system in May 2001, said Peoria attorney Patricia Benassi, who filed the age discrimination lawsuit Friday in U.S. District Court in Peoria.

Poor evaluations that followed affected their pay and threatened their jobs if performance ratings didn’t improve, the lawsuit alleges. Benassi said some employees retired, fearing they might lose their jobs, medical insurance and other benefits. Younger employees whose performance was similar or worse received better ratings, the lawsuit claims.

Caterpillar spokesman Lori Porter said the evaluation process was developed to improve performance by rewarding high achievement. The company is reviewing the lawsuit and the process, "but our early review reveals there is no merit to the allegations," she said.

Employees are rated based on goals developed in meetings with their supervisors, she said. The process is used to evaluate about 26,000 management and non-production salaried employees, she said.