SIDNEY, Mont.-Investigators on Wednesday said they still aren't certain what caused the explosion Saturday at an oil well site near Sidney in far northeast Montana near the North Dakota border.
The explosion, which could be felt 3.5 miles away in Sidney, damaged a nearby shop but injured no one. Sidney is about 45 miles southwest of Williston, N.D.
The tank sat on a well site dubbed Jennifer 134H, said Richland County Sheriff John Dynneson. It is owned by Newfield Production.
At 9:48 a.m. on Saturday, the tank exploded and could be felt in Sidney, Dynneson said. A nearby home was not damaged, according to reports, but Dynneson said a nearby workshop suffered significant damage.
"The only area that was damaged was where the shop was located," he said.
Equipment at the well site was heavily damaged as well. The Sidney Volunteer Fire Department responded, but its efforts were hampered by extremely cold weather.
Cindy Hassler, a spokeswoman for Newfield Production, said Wednesday the investigation into the cause of the explosion continues.
There was no oil contamination to the area, she said.
Hassler said crews were dismantling the site equipment slowly as part of that investigation. The well was not actively producing at the time of the incident, and no employees were present.
John Mercer, who lives a quarter-mile from the site, said he heard at least two explosions. When he stepped outside, he said he saw plumes of smoke coming from the site.
When he got closer, he said he could see that the tops of three above-ground tanks had blown off.
"And they were all burning," Mercer said.
The tops of the tanks could be found hundreds of yards from the well site, Mercer said.