By David Bailey
MINNEAPOLIS (Reuters) - A natural gas line exploded in Minneapolis on Thursday, shooting flames several stories into the air, forcing the evacuation of businesses and homes and bringing traffic to a standstill on major highways.
No injuries were reported. Gas to the distribution line was shut off and the huge plume of flames was allowed to burn itself down after about an hour, fire and city officials said.
"When this thing built up pressure and it exploded, the best thing that we can do is let it burn until we can get it shut off and that is exactly what happened in this instance," Assistant Fire Chief Cherie Penn told reporters.
The fire department did not put any water on the blaze.
"The intensity at which this fire was burning it wouldn't have done anything," Penn said.
Several city blocks were evacuated including an elementary school, a day care facility and a grocery store located next to the explosion. An Interstate 35W overpass near the site showed some charring, but investigators found no damage.
All major roads were reopened by midday except for an exit ramp to a local street, said Kent Barnard, a Minnesota Department of Transportation spokesman.
CenterPoint Energy owns the natural gas line where the fire occurred. Local media video footage shot from helicopters showed a massive crater at least 30 feet by 20 feet in a street across from a grocery store parking lot.
A witness told television station WCCO that people immediately exited the grocery store through rear doors to get around the extreme heat from the flames.
A handful of vehicles parked midway across the parking lot had exterior damage and letters on the store marquee appeared to have melted in heat from the flames.
Emergency workers had reduced the evacuation area by late morning and residents were being allowed back except in the immediate site, CenterPoint spokeswoman Becca Virden said.
"That part will remain closed down until the repairs are made and we can return it to normal operations," she told reporters.
Gas was cut off to the immediate area of the fire for about an hour and otherwise no customers lost service, Virden said. The cause of the fire was under investigation, she said.
(Reporting by David Bailey; Editing by Jerry Norton)