The California city’s mayor London Breed said the rapid change of the “global picture” so local officials “need to step up preparedness”.
There have been no reported cases of Covid-19 in San Francisco but Mayor Breed said declaring an emergency would help protect the city from harm.
“Although there are still zero confirmed cases in San Francisco residents, the global picture is changing rapidly, and we need to step up preparedness,” she said in a statement Tuesday.
“We see the virus spreading in new parts of the world every day, and we are taking the necessary steps to protect San Franciscans from harm.”
While three people have been treated for COVID-19 at San Francisco hospitals, there have been no confirmed cases in the city.
Her announcement followed the US Centres for Disease Control and Prevention’s warning that the virus is likely to continue to spread.
“Ultimately, we expect we will see community spread in this country,” CDC Director Nancy Messonnier said.
“It’s not so much a question of if, but a question of when.”