Well control experts succeeded in plugging a runaway Chesapeake Energy Corp. oil well that had been spewing natural gas and drilling mud since last Tuesday near the town of Douglas, WY, in part of the Niobrara Shale formation in Converse County. Workers managed to reduce the pressure and regain control by plugging the well with mud.

The workers began the recovery operations at 9:30 a.m. MDT and before noon the well was plugged, according to Tom Doll, supervisor for oil and gas at the Wyoming Oil and Gas Conservation Commission (OGCC) as reported by Associated Press.

Houston-based Boots & Coots and its parent company, Halliburton, conducted the well control work, pumping mud down the wellbore through steel lines to stem the emissions and avoid the threat of an explosion and fire.

The OGCC has been monitoring air quality and found that there was no harm to public health or the environment, according to a spokesperson for the governor.

The Chesapeake spokesperson at the scene said air sampling results from surrounding areas continue to register as normal. Residents who voluntarily evacuated earlier in the week, however, could choose to remain in area hotels at the company’s expense if they wanted, said Chesapeake’s Kelsey Campbell.

The incident occurred during a procedure to install steel well casing on Tuesday. The cause was under investigation. No one was injured, and there was no threat to air or water, according to state and federal officials.