A liquid propane tanker exploded on an Indianapolis highway ramp on Thursday morning, shooting a fireball of flames and black smoke into the sky and closing a section of two of the city's major expressways.

The explosion closed Interstates 69 and 465 on the northeast side of the city.

The tanker's driver was taken to a hospital with burns that didn't appear to be life threatening, said Lawrence Township Fire Marshal Dick Groves. At least one other person also was taken to a nearby hospital, he said. No other details were immediately available.

Lonnie Hood said he was working near the highway ramp when he heard the explosion.

"We seen a big massive fireball like you wouldn't believe," he told WTHR-TV. "It was a massive explosion. It just roared in my chest. It was unreal."

He said he and another man helped pull the driver out of the burning tanker.

"Me and another guy pulled him out of there and just drug him down the road here and his whole truck blew up," Hood said.

Other witnesses said they had to put their cars in reverse to escape the flames, which charred billboards and a cellular phone tower.

"People near the explosion got out of their cars and ran from the scene," witness Sage Kopronica told WISH-TV.

Groves said the "humongous" explosion happened after the truck rolled, with the cab and tanker separating and catching fire underneath an Interstate 465 bridge. He said the fireball could be seen and the heat felt two miles away.

"The flames were licking the bridge all around it," Groves said.

State Police Sgt. Anthony Emery said the highways near the explosion scene would be closed until engineers reviewed the bridge for safety.

IBJ will update on this story later today.