CHEYENNE, Wyo. (AP) -- Authorities won't be able positively to identify the three workers killed in an oilfield explosion in eastern Wyoming until autopsies are performed on them, a company spokeswoman said Tuesday.
The blast occurred Monday at an oil production site on a private ranch, about 40 miles northeast of Casper.
It came as the men worked on a fuel line supplying a heater treatment facility that separates oil from water as the substances are pumped from the ground, said Dennis Neill, spokesman for Samson Resources Co. in Tulsa, Okla.
The blast sparked a 10-acre fire before it was brought under control.
The names of the men killed have not yet been released. The workers were employed by contractors that Samson had hired to bring an oil well back into production at the site, Neill said. The well wasn't involved in the explosion or the fire on the Hornbuckle Ranch.
"Obviously we're very concerned about the family and friends in this situation," Neill said.
Tina Wells, spokeswoman for Samson, issued a statement Tuesday saying that the bodies of the men would be taken to Colorado for autopsy and positive identification. She said she didn't know how long it would take to identify them.
"It takes an autopsy to get a positive identification in this case," Wells said. "And the authorities will not release any notification to you of who the victims might be until they have very definitive, positive identification."
Wells said the men worked for two local construction companies, identified as Wild West Construction and Double D Welding and Fabrication. Officials with the companies and Converse County Coroner Ross Gorman could not immediately be reached Tuesday for comment.
Wells said Samson has ceased construction work on other facilities in Wyoming until a preliminary cause of the explosion can be determined.
Wyoming, a top energy-producing state, for years has ranked among the highest states in terms of per capita workplace fatalities. Wyoming lost its title as the deadliest state in the nation for workers to Montana last summer, largely due to a slowdown in Wyoming's gas industry.
The Wyoming State Senate rejected a bill early last year that would have increased employer penalties for workplace safety violations. Then-Gov. Dave Freudenthal had urged passage of the bill, which industry groups supported.
The Wyoming Department of Workforce Services reported last week that the number of occupational fatalities in the state rose to 34 last year -- an increase of nearly 79 percent from the prior year. Of those 34 deaths, 10 were in the natural resources and mining sector. A new federal ranking of state workplace death rates based on per full-time worker will be available next spring, said Sara Saulcy, senior economist with workforce services.
According to preliminary figures from the U.S. Bureau of Labor Statistics, fatal work injuries nationwide in the private mining industry, which includes the oil and gas industry, increased by 74 percent nationwide last year to 172 deaths. Of that number, fatalities in the oil and gas industry accounted for 106, or about three-fifths, of the fatal work injuries. In 2009, 66 of the 99 mining industry deaths nationwide were in the oil and gas fields, according to BLS data.
J.D. Danni, manager of the Wyoming Occupational Safety & Health Administration program, said Tuesday that Samson hasn't received any citations from the state in recent years.
The state of Wyoming is investigating the blast through its Department of Workforce Services.
Danni said his office has two investigators on the scene to determine the cause of the explosion and whether any workplace safety violations contributed to it.
Converse County Sheriff Clint Becker said Tuesday he didn't believe there were any witnesses to the explosion.
Associated Press writer Bob Moen contributed to this report.