A suspicious package near the site of the 1906 San Francisco Earthquake commemoration ceremony on Market St. Thursday morning forced an early-morning gathering of a couple of hundred people to move to Union Square, police said.
San Francisco emergency officials activated a warning siren Sunday afternoon, triggering some confusion among residents.
A false alarm was sent out Wednesday morning by Contra Costa Health Services warning Martinez residents that there was an emergency at the Shell refinery.
Tours of Alcatraz Island were canceled after a false fire alarm Sunday afternoon prompted the evacuation of about 1,100 people from the popular San Francisco tourist attraction.
A malfunction caused an emergency warning siren to sound for about half an hour in Richmond Tuesday morning, Contra Costa Health Services officials said.