A milestone nearly two years in the making has arrived in Los Angeles County.

California’s most populous county relaxed its public health order on Friday to allow unmasking indoors at restaurants, bars and other businesses for people who show proof of vaccination. Employers also can permit their workers to remove their masks if they are vaccinated.

The revised rules went into effect at 12:01 a.m. Friday.

All customers must still prove either that they are vaccinated or have a recent negative COVID-19 test. Following a statewide rule, unvaccinated customers must continue to wear masks indoors unless they are actively eating or drinking.

The city of Los Angeles said it will follow LA County’s lead.

The rule revision comes a day after the Biden administration said it will significantly loosen federal mask-wearing guidelines to protect against COVID-19 transmission on Friday. The decision means most Americans will no longer be advised to wear masks in indoor public settings.

LA County lagged behind the state as a whole, which lifted its indoor mask mandate for vaccinated people for most businesses last week. Most of California’s 58 counties quickly followed suit.

However, Santa Clara County still requires universal indoor masking.

In issuing the changes, the county Department of Public Health cited lower COVID-19 hospital admissions and “the effectiveness of the vaccines in reducing severe illness.”

About 70% of LA County’s 10.3 million people have been fully vaccinated and about a third of residents also have had a booster shot.

LA County officials have come under increasing pressure to ease the masking requirement. Janice Hahn, one of five members of the county Board of Supervisors, argued last week that the county should follow the state’s lead.

“I believe we are beginning to lose the trust of the people,” she tweeted on Feb. 15. “We already saw thousands of people flagrantly violate LA County’s (outdoor) mask mandate at the Super Bowl … Keeping mandates in place that aren’t followed just erodes the credibility the public has in our ability to make good, sound decisions.”

Last week, California became the first state to formally shift to an “endemic” approach to the coronavirus with Gov. Gavin Newsom’s announcement of a plan that emphasizes prevention and quick reaction to outbreaks over mandated masking and business shutdowns.

The milestone, nearly two years in the making, envisions a return to a more normal existence with the help of a variety of initiatives and billions in new spending to more quickly spot surges or variants, add health care workers, stockpile tests and push back against false claims and other misinformation.

It’s likely to be a few more weeks before Los Angeles County feels comfortable removing all indoor masking requirements. That will happen when the county’s rate of COVID-19 transmission — listed as high — reaches the moderate level of fewer than 730 cases a day over seven days.

On Wednesday, the county reported 1,934 additional COVID-19 cases and 36 deaths. There were 1,204 people hospitalized.

California still requires indoor masking for everyone in elementary schools, on public transportation or in certain group facilities such as nursing homes, child care centers, prisons and homeless shelters. However, the state Department of Public Health could announce changes to the schools requirement on Monday.