MINNEAPOLIS  - The U.S. Department of Labor is investigating certain investments, expenses, loans and distributions made by 3M Co.'s pension plan.

The Star Tribune reports  that the Maplewood company revealed the investigation this week in a Securities and Exchange Commission filing.

The company's quarterly report says the Department of Labor notified the company in April 2015 about the probe.

A 3M spokeswoman said that the company would have nothing to say beyond what was written in the recent quarterly report. The government did not return a call seeking comment.

The company's annual report in 2016 showed that the pension plan was worth nearly $19.7 billion.