A veteran firefighter was taken to surgery after he was injured in a fire and gas explosion while he was off duty at his Lawrenceville home Monday afternoon.

John Cunningham, a captain with the Milton Fire Department, was burned on his hands, forearms and torso and was taken to Grady Memorial Hospital, his wife, Tammy Cunningham told reporters at the scene.

Cunningham was working in his basement around 1 p.m. when police and firefighters received a report of a fire and series of explosions at his home on Sundale Drive.

The fire was quickly extinguished and hazmat and arson investigators were on the scene trying to determine the cause, said Jake Smith, a Gwinnett County police spokesman. Smith said the investigation has revealed no criminal activity.

Cunningham said he had been working on an air-conditioning unit in the house, Smith said.

Gwinnett County Arson Investigators preliminarily found there was a gas explosion in the area of the basement where Cunningham was working.

“It seemed there was a natural gas explosion in proximity to where he was working,” said Lt. Colin Rhoden, spokesman for the Gwinnett Fire Department.

The majority of the fire was confined to the front and side of the house. “There is substantial damage,” Rhoden said. Bricks were knocked off the front of the home, and a railing on the front porch also was down, he said. He said three family pets died in the fire.

Tammy Cunningham said her husband called her at work and said “I needed to come home.

“He was awake, alert and talking with the rescue unit when we got here,” she said.

“He said the house exploded, and he got caught in the fire.”

Cunningham, 49, has been with the City of Milton Fire Department since its launch in May 2007. Previously, he spent 26 years at the Fulton County Fire Department, where he retired.