State oil and gas regulators are blaming mechanical failure for a natural gas well blowout in eastern Wyoming last month.
The AP reports an investigation by the Wyoming Oil and Gas Conservation Commission also found that workers at the rig failed to properly engage part of the wellhead apparatus.
The blowout of the Chesapeake Energy Corp. natural gas well near Douglas occurred on April 27.
The well vented about 2 million cubic feet of gas and up to 31,500 gallons of oil-based drilling "mud" over nearly three days before Chesapeake and its contractors were able to control it.
The Oil and Gas Commission report says the integrity of the well itself was not compromised and the wellhead parts involved are being examined.