MAPLEWOOD, Minn. (AP) — The leading manufacturer of N95 masks in the U.S. says it has investigated 4,000 reports of fraud, counterfeiting and price gouging in connection with the product and filed 18 lawsuits as a result.

3M, based in Maplewood, is among the largest global producers of the N95 mask, which has been approved by the U.S. National Institute for Occupational Safety and Health and is considered the gold standard in protection against the coronavirus.

READ MORE: COVID In Minnesota: UK Variant Outbreak Linked To Youth Sports In Carver County, Officials Recommend 2-Week Pause

3M says courts have issued six temporary restraining orders and four preliminary injunctions so far to stop N95 sales that it says are unlawful.

READ MORE: More Than 1 Million Wisconsin Residents Have Been Vaccinated

The company says in some cases, it has led to criminal charges.

MORE NEWS: Faces Of COVID: Daryl Kruger, 82, Loved His Grandkids And The MN Twins

(© Copyright 2020 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)