CHEYENNE, Wyo. - The blowout of a gas well just south of the Montana border led to an evacuation order that affected about a dozen people and ended early Monday.

The voluntary evacuation of the subdivision west of Clark was ordered at around 6 p.m. Friday and lifted around 8 a.m. Monday, after the well was plugged with 1,300 barrels of heavy mud, said Dave Hoffert, on-scene commander with the Clark Fire District.

Hoffert said the blowout occurred Friday at about 2:30 p.m., shortly after the well was drilled on the Crosby Ranch just east of Shoshone National Forest.

Windsor Wyoming LLC, based in Oklahoma City, drilled the well. Excessive pressure caused the blowout, Hoffert said.

Twenty-six homes were in the evacuation area about four miles south of the Montana border. Besides the dozen or so people who were asked to leave, another 10 or so who arrived in the area over the weekend were asked to stay away, Hoffert said.

He said monitoring devices at no point registered an explosive quantity of gas at anyone's home in the evacuation area, which was 2½ miles long.

Property where homes were evacuated included the Crosby Ranch.

Deb Thomas, who was among the evacuated, said she was concerned about how much time elapsed before she was told to leave.

"How about those of us who were there from 2 o'clock to 7 o'clock breathing this stuff before anyone bothered to let us know what was happening?" she said.

Thomas, an organizer for the Powder River Basin Resource Council, said she also was concerned that the blowout contaminated the aquifer supplying water to homes. "We're looking at long-term monitoring to establish what's going on with our water," she said.

Windsor reached a settlement with the state in January for improperly disposing of at least 200 barrels of fluids at a home near Clark. The settlement called for Windsor to pay $5,000.