July 14 (UPI) — Authorities were searching waters near Alcatraz on Tuesday evening for two missing people after a pontoon boat carrying 19 people capsized off San Francisco, leaving one person dead and 16 others rescued.

The three-level vessel with 19 people aboard was reported on fire about 600 yards off the coast of Alcatraz at 3:35 p.m. PDT, San Francisco Fire Chief Dean Crispen said in a press conference. Though reported as a boat fire, no evidence of one was found.

Responders were deployed, with the police department’s marine unit arriving on the scene to find one person “severely injured,” he said. CPR was administered to the victim, who was transported to Gashouse Cove Marina on the shore, where they were pronounced dead.

Officers arrived to find people had fallen into the water while others were inside the top compartment of the vessel, he said.

Of the 16 people rescued, three were transported to California Pacific Hospital, he said, adding that they had sustained impact injuries when they fell from the boat.

Crispen said he spoke with several of the survivors who remained on shore.

“They’re incredibly upset,” he said. “They’re aware that there’s some serious injuries here. They’re concerned about their mates and they went out on the bay with and, obviously, we’re going to take good care of them here.”

A search involving 11 vessels was underway for the two missing people, he said, adding, “We are going to be continuing for hours to make sure we find these two people if possible.”

He said authorities believe the boat launched from a local yacht club, but that was being investigated. It was also unclear whether those aboard were wearing life vests.

All those aboard the boat appeared to be adults, though a dog that had accompanied them died in the incident, he said.

Alcatraz is a former island prison and a current tourist attraction that sees about 1.2 million visits a year, according to the National Park Service.