SAN FRANCISCO—San Francisco is requiring all workers at San Francisco International Airport to get vaccinated against COVID-19 or undergo weekly testing if employees are exempt.

The mandate announced Tuesday applies to all on-site personnel, of which there are about 46,000. Mayor London Breed’s office said the mandate, which goes into effect immediately, is the first for a U.S. airport.

Some airline companies have already announced vaccination mandates for employees. San Francisco also requires municipal workers to be inoculated.

Hawaii requires workers at state facilities, including airports, to show proof of vaccination or provide weekly verification that they’ve been tested at least once or twice a week with negative results.

“As SFO prepares for the upcoming holiday travel season, and the return of pre-pandemic passenger levels, we have an obligation to provide a safe airport facility for the traveling public and our on-site employees,” said Ivar C. Satero, the airport’s director.