An age-discrimination lawsuit against 3M Co. was granted class-action status Tuesday by a Ramsey County judge in a move that could include up to 6,000 current and former workers over the age of 45.

Five plaintiffs filed the lawsuit 3 1/2 years ago alleging that then-3M CEO Jim McNerney favored younger workers and helped institute pay, promotion, training and termination policies that "systematically harmed older workers." Those policies put older workers out of jobs, denied them coveted Six Sigma training and violated the Minnesota Human Rights Act, plaintiff attorneys alleged while seeking class-action status.

"3M's overt statements about its preference for younger employees in decisions such as selections for leadership training and promotions led us to make challenges beyond [the traditional] discriminatory terminations" complaint, Sprenger & Lang attorney Susan Coler said.

3M officials vigorously denied the allegations and dismissed Tuesday's ruling as insignificant.

"This is an interim pretrial ruling and does not in any way address the merits of the plaintiffs' claim, which 3M believes to be groundless," spokeswoman Donna Fleming Runyon said. "... We will continue to vigorously defend against them."

3M attorneys challenged the plaintiff's request for class-action status during a hearing before a packed courtroom in December. Defense attorneys argued at the time that the plaintiffs skewed promotion and pay numbers by leaving out the entire executive management team in its age calculations.

"Of course 3M is not taking the position that older employees are less valued than younger employees," 3M attorney Tom Tinkham of Dorsey & Whitney told Ramsey County District Judge Gregg Johnson at the time. "The fact that 3M's leadership is represented almost entirely by older workers disproves their point." Tinkham also argued that the true size of the group of people involved in the suit was not 5,906 workers as claimed by plaintiffs, but more like "200 to 300."

Johnson's decision for class action means any number of current and former workers can join in the lawsuit, which was originally filed in December 2004.

"It's a procedural thing, but a big thing. It means the case is going forward, to either a trial or a settlement of some sort," Sprenger & Lang spokesman Jamie Diaferia said.

A half dozen current and former employees said privately that 3M's culture changed under McNerney, who left 3M in 2005 to become the head at Boeing. Even now that he's gone, workers older than 50 have said they are still not given training and job opportunities because of their age.

Their lawsuit seeks millions of dollars in damages and a court order for 3M to change its business practices. It also seeks punitive damages and up to three times any economic losses suffered by class members.

Dee DePass • 612-673-7725