https://www.mercurynews.com/2020/04/29/costco-will-require-face-masks-for-shoppers-workers-to-combat-virus/

Beginning next week, you won’t see many mouths or noses at Costco.

The bulk grocery chain has announced a change to its policy in the age of coronavirus: As of May 4, all shoppers over the age of 2 must wear face coverings. The only exceptions are for those who can’t wear a mask due to a medical condition.