Another age-discrimination lawsuit has been filed against 3M, this one by about 50 current and former employees in California federal court.

The complaint alleges that since 2001 the company routinely has passed over people older than 45 in its selection of management trainees. The company fires or forces older workers to resign or retire, it says.

A similar lawsuit is working its way through the Minnesota court system. The Califonia lawsuit has been filed as a class-action, which attorneys say could include more than 6,000 plaintiffs.

Dow Jones Newswire notes that the lawsuits come at a time when 3M is grappling with a drop in demand for its products and other challenges.