CONTRA COSTA COUNTY, CA — Face coverings will be required in public and at essential businesses in Contra Costa County beginning Wednesday, the county health officer announced Friday.

The order applies to all workers and visitors at essential businesses, like grocery stores and medical facilities, and public transit and government workers who interact with the public. People will be required to wear a mask when waiting in line or riding public transportation. The masks can be made of cloth, fabric, or other materials that allow breathing while covering the nose, mouth, and lower part of the face. County health officer Dr. Chris Farnitano said medical-grade masks are not required, and a T-shirt or bandana is an acceptable substitute. Masks with a one-way valve for easy breathing do not meet the requirements because they can release respiratory droplets into the air.

"We now know that a significant number of people with COVID-19 lack symptoms, or become infectious before they start showing symptoms," Farnitano said in a news release. "That is why we all need to start wearing cloth face coverings in public settings where it's sometimes hard to maintain physical distancing, such as standing in line at the store." Businesses will be required to notify their customers about the new rule. Workers don't have to wear masks in their personal office, but have to put one on around other people.

The order doesn't apply to people driving cars alone or with members of their household, but the county said people should always carry face coverings in case they encounter others in public. Anyone doing strenuous exercise should stay as far as they can from other people, especially while breathing heavily, and wear a mask or cross the street if possible. Children under two years old do not have to wear a mask due to the risk of suffocation, and children 12 years and younger are also exempt.

All county residents are asked to practice social distancing of at least six feet, and continue complying with the regionwide shelter-in-place order currently in place until May 3.