Five workers were injured after a fire and tank explosion at a natural gas field in western Wyoming on Friday, officials said.
Police said they received multiple calls about a blast at about 10:18 a.m. local time at Encana Corp's Antelope 91-29H facility in the Jonah Field near Pinedale, about 230 miles west of Casper.
One of the injured workers was airlifted to hospital in critical condition and the others were taken by ambulance to a local clinic and hospital, according to Encana Oil & Gas USA spokeswoman Bridget Ford.
"We know that some welding work was being conducted on the condensate tanks on location, however the exact reason for the explosion is not known at this time," she added.
Firefighters contained the blaze, which burned out by 1 p.m., Ford said.
A drilling rig operating near the facility where the incident occurred was not affected, according to Ford. She said there was no apparent environmental impact.
"Our thoughts are with our friends and co-workers that were hurt today, and their families, Ford said.
The Occupational Safety and Health Administration is investigating the incident.