Clayton County authorities are working to determine what sparked a predawn fire that has destroyed a large home on Lake Spivey in Jonesboro.

Fire crews received a report of a fire at the home in the 2500 block of Emerald Drive about 6:10 a.m., said Capt. Walter L. Barber with Clayton County Fire & Emergency Services.

Barber told The Atlanta Journal-Constitution that the house was fully engulfed in flames when firefighters arrived.

“Units were able to get it under control and prevent any spread of the fire [to nearby homes],” Barber said. “Unfortunately, it was a total loss.”

The 87-year-old resident of the lakefront home and her caretaker got out of the house.

Barber said one of the 40 to 50 firefighters battling the blaze was transported to a local hospital to be treated for heat exhaustion. That firefighter is “doing okay,” Barber said.

“This type of fire is labor intensive,” he said. With the house sitting a “considerable distance from the roadway, it requires a lot of manual labor getting hoses and water to the fire.”

Neighbor Don Gaines was impressed with the number of firefighters working to douse the fire, telling The AJC, “I didn’t know we had this many fire trucks in the county.”

Gaines said he was in bed when he heard sirens coming to a stop near his home.

“We have a lot of elderly people in the neighborhood and I thought it was an ambulance or something,” he said.

“My wife was already up and she said Mattie Harris’ house is on fire,” Gaines said. “I said, ‘are you sure it’s not an ambulance?’ and she said, ‘no, come look.’”

Gaines, who has lived on Lake Spivey since 1977, said Harris and her husband, who died about 10 years ago, moved into their home in the mid-1980s.

“It was a beautiful house, probably 10 or 12,000 square feet,” he said.

She has a son who lives on the other side of the lake, Gaines said.

“She’s a friend and a neighbor and she lost everything,” he said.