DEER PARK, Texas, Sept 17,  (AP): A towering flame gradually subsided Tuesday morning in the aftermath of a massive pipeline explosion after a vehicle drove through a fence and struck an above-ground valve, officials said. Deer Park officials said police and local FBI agents initiated investigations and found no preliminary reports that would suggest a coordinated or "terrorist” attack and that "this appears to be an isolated incident.”

The investigation included efforts to learn more about the driver of a vehicle that was incinerated by the pipeline explosion as flames scorched the ground across a wide radius, severed adjacent power transmission lines and ignited homes at a distance. Police did not provide any information about the person's condition.

An evacuation area included nearly 1,000 homes and initial shelter orders included schools. Operators shut off the flow of natural gas liquids in the pipeline, but so much remained in the miles of tubing that firefighters could do nothing but watch and hose down adjacent homes. Deer Park Mayor Jerry Mouton Jr. described intense heat from a fire that endured for more than 12 hours as ladder trucks showered houses from above.

"A lot of the house structures that are adjacent to that are still catching on fire even though we’re putting a lot of water on them,” Mouton said at an afternoon news conference. A spewing flame still lit up the sky at sunset Monday. Firefighters initially were dispatched at 9:55 a.m., after an explosion at a valve station in Deer Park, adjacent to La Porte, rattled homes and businesses, including a Walmart.

Deer Park officials said an SUV drove into the valve after going through a fence on the side of the Walmart parking lot. At the news conference, officials said only one person, a firefighter, sustained a minor injury. Later, Deer Park spokesperson Kaitlyn Bluejacket said four people were injured. She didn’t provide details about the severity of the injuries. Harris County Judge Lina Hidalgo said in a statement that 20 miles (32 kilometers) of pipeline between the two closed valves had to burn off before the fire would stop.