WINNIPEG -- London Drugs is recalling a five-piece mask set over concerns about small holes that could impact their effectiveness.

The company confirmed the news in a statement to CTV News on Wednesday, saying it voluntarily recalled the five-piece KN95 mask product.

A spokesperson for London Drugs said some of the units, “were shipped with small holes along the seams of the masks, which may affect the masks’ filtration efficacy.”

The products were sold across Western Canada as of September 1.

“The product supplier has advised London Drugs that it estimates about 18 per cent of the masks sold in stores may have had the noted deficiency,” the company said in a statement.

A post on the company's website said the issue was due to a manufacturing error.

London Drugs said it has notified Health Canada of the deficiency, and added it would work with the supplier and follow guidance from the federal agency about further review of the masks and the recall.

“The health and safety of our customers and community is of utmost importance to London Drugs and we are taking this matter very seriously,” the spokesperson said.

The impacted item has the UPC number 0-62823-74870-5. 

Customers can bring back the masks to the store for a refund. If they have any questions, they can call the London Drugs Customer Care Centre at 1-888-991-2299.