3M Co. has offered to pay up to $12 million to settle a lawsuit that accused the diversified industrial company of discriminating against older workers in performance evaluations, promotions and layoffs.

About 7,000 current and former salaried, nonexecutive employees would be covered under the proposed settlement filed jointly by the company and the plaintiffs Friday in Minnesota District Court. The agreement would have to be approved by the court before being implemented. The settlement does not include any admission of liability by 3M for its employee practices.

“The proposed settlement agreement provides a reasonable resolution that allows the company to avoid ongoing investments in time and legal fees,” Marschall Smith, senior vice president and general counsel, said in written statement. “We believe the resolution will allow the company and our employees to focus on growing our business and serving our customers.”

Under the agreement, those eligible for payments are all older than 46 years old. The administration of any payments would be handled by an outside party.

The lawsuit, which was filed in December 2004, claimed the St. Paul, Minn., company violated Minnesota’s human rights statute prohibiting workplace discrimination. The lawsuit cited 3M’s deployment of its Six Sigma program, a widely used corporate-improvement strategy popularized by General Electric Co. that constantly tracks performance and quality against benchmark goals.

The program at 3M was implemented by former CEO James McNerney, who came to 3M from GE in 2001. McNerney left the company in 2005 and is now chairman and chief executive of aircraft maker Boeing Co.

The plaintiffs accused 3M of consistently marking down older workers in Six Sigma performance reviews, setting unrealistic goals and denying veteran employees the training and resources to reach their goals or improve their performance. The complaint said these employees were passed over for promotions, given smaller raises than younger employees and disproportionately targeted for layoffs.

3M, whose product lines include Post-It notes, Scotch tape, sand paper, furnace filters and thousands of other products and materials, denied the allegations in the complaint and reiterated Friday that its human resources practices are recognized as fair and in compliance with state and federal laws.

3M’s stock was recently trading up 0.36 percent at $89.02 a share.