Natural gas service to an area of downtown Durham, NC, remained off late Wednesday afternoon following a deadly pipeline explosion and fire that killed one person and injured at least 15 people, according to Dominion Energy.

According to some reports, a contractor hit a 2-inch gas line under a sidewalk, causing an explosion that damaged five buildings. However, an investigation was underway and no cause had been determined.

The City of Durham said firefighters were dispatched at 9:38 a.m. to a gas leak in the 100 block of North Duke Street. City officials said firefighters and Dominion employees were on the scene investigating the leak when the explosion occurred at around 10:07 a.m. The explosion caused a fire and a partial building collapse. A firefighter and a Dominion employee were said to be among the injured.

"Until the investigation is complete, we don't know that's the source of the gas leak," Deputy City Manager Bo Ferguson told the Charlotte Observer. The Durham County Fire Marshal is overseeing the investigation, he said.

Dominion said crews from subsidiary PSNC Energy were on the scene at about 10:30 a.m. and shut off gas to the area at about 11:10 a.m.

The explosion reportedly damaged a large collection of rare Porsche cars that were stored in an adjacent building.

"Dominion Energy's thoughts and prayers are with those impacted by this tragic event as well as their families," the company said. "We are continuing to work with emergency officials on scene and updates will be issued when more information is available."

PSNC serves a 28-county service area in North Carolina and provides natural gas to more than 581,000 customers. Dominion, which was ranked as the nation's fourth-largest gas and electric utility in 2017, serves 7.5 million energy customers in 18 states.