Smoke from the home at 53 Victory Lane was visible for at least a mile when the fire started after 7 p.m. Nazareth resident Brielle Arnold was at a nearby park when she saw smoke and followed it where she saw "the whole house in flames."
"They were coming out of the top, out of the sides, out of everywhere," she said.
Mario Andretti, reached by phone while dining in Clearwater Beach, Fla., said he was saddened to learn his former home had been damaged by fire.
"That was our first house," he said. "I've only built two in my life."
Andretti, and his wife, Dee, raised their three children — Michael, Jeff and Barbie — at the Victory Lane address.
The auto racing legend said he learned of the fire by text message from his daughter and a phone call from a former neighbor.
Andretti built the home in 1968 when the street was named Market. After his victory in the Indianapolis 500 in 1969, the street was renamed to Victory Lane. The Andrettis lived at the home until 1998 when they built their second home in Bushkill Township.
"Of course we have so many great memories from living there," he said. "My parents lived just a block away.
"To see the photos with the fire engines in front of the house is very sad."
Vigilance Hose Fire Chief Danny Keenhold said the home is a loss. When he arrived, flames were shooting out of the garage, which is where firefighters believe the fire started.
Keenhold said firefighters would return Friday morning to try to determine the fire's cause.
The fire blew out bay windows on the garage. Visible through the open garage and front doors, the interior of the home looked black.
The fire was brought under control in about an hour. Smoke permeated the neighborhood after the home was ablaze.
Tatamy resident Raelyn Campanaro was among the onlookers at the fire. She said she went to school with Tabitha Kardelis, who lives in the home with her father, Jamie Kardelis; her mother, Shelley; and her brother, Tanner. Online property records list Jamie and Shelley Kardelis as the property owners.