Divers were in Lake Wylie in attempt to retrieve the boat that caught fire Wednesday afternoon. Officials hope to order determine how the explosion occurred.
Around 2:30 p.m., a pontoon boat with a small crane is in the water with drivers who are trying to find the boat.
Once they do, they'll need to evaluate its condition before raising it from the water.
Officials estimate the boat capsized after catching fire a couple hundred feet from the fuel dock.
Four members of a Charlotte family remain in hospitals after the boat they were on burst into flames in the Tega Cay Marina Wednesday afternoon.
The father and his 11-year-old son are being treated for serious burns at the burn center at UNC Chapel Hill, said Lt. Robert McCullough of the state's Department of Natural Resources. Two other sons are being treated at Carolinas Medical Center for less severe burns, he said. One has a broken leg.
Six people were aboard a 37-foot cabin cruiser on Lake Wylie at the Tega Cay Marina refueling before the boat caught fire, McCollough said. A family of five and a friend-- parents and three boys and one of their girlfriends -- were on the boat.
The mother of the family was treated and released from the Charlotte hospital, and the girlfriend was not injured.
Onlookers rushed into the lake to help pull the family from the water.
Officials are still investigating the cause, and the boat is expected to be raised from the water this afternoon after a dive team evaluates the boat's status.
A preliminary investigation determined the boaters refueled about 1:30 p.m. and had pulled away from the dock when it exploded, said Mike Channell, York County Emergency Management coordinator.
Five other boats and part of the dock were damaged by the fire, DNR Lt. Sandy Young said.
"The explosion shook my house," said Carol Earnheart, who lives on the lake about two houses from the marina. "I panicked before going outside to see what was going on. I've been here 21 years and never saw anything like this."
Scott Spivey, a boating safety instructor with Lighthouse Marine Services, said he was at the marina when the fire started.
He heard an explosion and "everything was just engulfed in flames," Spivey said. "You could tell two of the kids were burned and one of the adults were burned."
Richard Mason was working on a soft drink machine about 100 yards from the dock when he heard the explosion.
"I went down to the end of the pier. All of [the victims] were above the water, and I went in and pulled a couple of them out," Mason said. One of the four was a boy with an apparent broken leg, he said.
"Other people heard (what was happening) and they came down and started pulling people out, too. We were trying to get them out as quick as we could because we didn't know if the pumps were going to explode."
Officials pulled the boat into deeper water as it continued to burn. The boat was still smoking hours after the incident.
Young said officials won't be able to complete the investigation until the boat is pulled out of the marina, which could happen today, weather permitting.
Wednesday's explosion was the second involving a boat on a Charlotte-area lake in three years. In 2008, a boater on Lake Norman died when a spark ignited gas vapors on a house boat.
While the cause of Wednesday's explosion has not been determined, Spivey said boaters should properly vent their vessels after fueling by using the blower to sift gas away from the engine compartment. He said boaters should then make sure they don't smell gas fumes before starting the engine.
He said boaters often skip this step, and it can lead to fires.
The S.C. DNR and York County Emergency Management officials are continuing the investigation. DNR does not expect to file criminal charges in this incident, McCullough said.
The Fort Mill Times contributed