One person died, two others remained missing, and 16 people were rescued Tuesday after a three-deck pontoon boat sank near Alcatraz Island in San Francisco Bay, prompting a large search-and-rescue operation involving divers, helicopters, and multiple emergency agencies.

San Francisco Fire Chief Dean Crispen said crews responded shortly after 3:30 p.m. to reports of a fire aboard a vessel about 600 yards from Alcatraz. When firefighters arrived, they found the pontoon boat largely submerged, with its motor still running and leaking fuel. Authorities later said they found no evidence that a fire had occurred.