3M Co. has agreed to pay up to $12 million to settle an age-discrimination lawsuit with as many as 7,000 current and former employees.

The 2004 lawsuit targeted the company's performance-review system, alleging that older workers were disproportionately downgraded. It also accused the company of favoring younger employees for certain training opportunities that could fast-track them for promotions.

The Maplewood-based industrial company and plaintiffs filed a joint motion Friday for preliminary approval of the settlement.