The woman had been taken to Regional Medical Center Bayonet Point in critical condition on Sunday and died at 10:42 p.m., the hospital spokesman, Kurt Conover, said on Monday. Beth Fifer, an assistant to the chief executive officer of the Tropical Breeze Casino, said on Monday that she had spoken to the family of the deceased woman but had no further information.

The Coast Guard is investigating the cause of the fire, Michael De Nyse, a Coast Guard spokesman, said in an interview on Monday.

About a dozen other people were treated for exposure, anxiety and other minor injuries, Chief DeCanio said on Sunday.

Chief DeCanio said on Sunday that quick thinking by the shuttle boat’s captain helped avoid a disaster. Shortly after the vessel left the dock, the captain spotted smoke spewing from the engine room and decided to turn around. But the fire rapidly grew, so the captain steered the boat toward the shore, allowing passengers to jump off into shallow water, Chief DeCanio said.

“Another quarter-mile out, this would have been a tragedy,” he said.

The Sun Cruz shuttle boat makes several trips daily from the city of Port Richey to a casino boat about three and a half miles offshore, in international waters where gambling is legal.