SCOTTSBORO, Ala. (AP) — Investigators on Tuesday were focusing on one boat in particular as a possible cause of a massive Alabama marina fire that killed eight people, and using floating barriers to contain environmental damage.

The dock at Jackson County Park Marina is on a wide creek that feeds into the Tennessee River, but it did not appear pollution from oil, propane gas and other materials had reached the main water, said Fire Chief Gene Necklaus.

Burned propane tanks were visible in water near the marina, along with an oily sheen, and the smell of gasoline was still strong more than 24 hours after the blaze was extinguished. But state and environmental officials who were on hand said any environmental damage appeared to be minimal.

Thousands of feet of floating barriers were being used to contain the pollution and a crane was put in place in deeper waters on Tuesday to lift sunken boats, some longer than 40 feet. At least five of the watercraft had been removed by Tuesday but as many as 30 more remained at the bottom of the creek.

Crews will raise each sunken craft and check inside each to determine whether additional people may have died, Necklaus said, but officials were optimistic that the death toll would not rise.

Investigators hadn’t determined the cause of the blaze, which erupted shortly after midnight Sunday, but Necklaus said they were narrowing their focus to a vessel that was docked in an area where witnesses said the flames began.

“It’s fair to say they are at least looking at one boat in particular, not to say that they won’t rule that out and move on to the next area,” he told a news conference.

Already removed from the water, the boat was taken to a secure area for examination, he said.

Witnesses said wind quickly swept flames down a wooden dock where an undetermined number of people were sleeping on boats. Residents described a desperate fight for life, with some piling into boats to get away and others diving into water that was in the mid-50s to swim for their lives.

A Red Cross representative said about 25 people were believed to have lived in boats at the dock full time,but it was unclear whether they were all there at the time of the fire or whether other visitors were present.