As of 11:59 p.m. on April 17, essential workers in San Francisco — including those who work at restaurants open for delivery and takeout — are required to wear face coverings, as are citizens out to pick up meals, shop for groceries, or do other essential tasks.

The new policy was announced by San Francisco Mayor London Breed and city Director of Health Dr. Grant Colfax on Friday afternoon, and was enacted, they say, to help “prepare for future lifting of shelter-in-place.”

According to Breed’s announcement, “everyone in San Francisco will be required to wear face coverings when they are outside of their homes for essential needs, including waiting in line for or inside of a grocery store.”

Businesses like grocery stores, restaurants, and other essential businesses are also required to “inform customers about the need to wear a face covering” and must “refuse service to anyone not wearing a face covering.”

Restaurant workers must now “wear a face covering when at work in most settings, when interacting with the public or co-workers.”

To comply with the order, “face coverings should cover the nose and mouth and fit securely,” and can be “a manufactured or homemade mask, a bandanna, scarf, towel, neck gaiter, or similar item.”

The rule takes effect as of 11:59 tonight, but won’t be formally enforced until 8:00 a.m. on April 22. According to Breed’s office, “the order does carry the force of law, and noncompliance is a misdemeanor punishable by fine, imprisonment, or both.”

The full order can be read here, and here’s a summary of its main points:

For the public, face coverings will be required:

While inside or waiting in line to enter an essential businesses, like a grocery store or pharmacy.

When seeking health care.

When waiting for or riding transit.

When entering facilities allowed to operate under the Stay Home Order (such as government buildings.)

Businesses must:

Inform customers about the need to wear a face covering, including posting signs;

Take reasonable steps to keep people who are not wearing a face covering from entering their business, and

Refuse service to anyone not wearing a face covering.

For essential workers and transportation workers:

All workers and volunteers at essential businesses, operating public transportation, or operating other types of shared transportation must wear a face covering when at work in most settings, when interacting with the public or co-workers.

Workers doing minimum basic operations, like security or payroll, essential infrastructure work, or government functions must wear a face covering when others are nearby or when they are in areas that the public regularly visits.

Face coverings are not required to be worn when by people who are: