Hydrocarbons found in Wyo. stock well

Trace amounts of hydrocarbons have been found for the first time in a livestock water well bordering a natural gas drilling area in southwest Wyoming.

Officials say the concentrations of hydrocarbons found in the well were minuscule and posed no threat to human or animal health. But they were still concerned.

"We found this detection for hydrocarbons, which shouldn't be there, and we're trying to figure out how it got there and where it's coming from," Chuck Otto, director of the Bureau of Land Management's office in Pinedale, said Tuesday.

The stock well is just south of the town of Boulder, in Sublette County. The well is on the outside edge of the Pinedale Anticline, where gas drilling has been occurring, Otto said.

The BLM is close to issuing a final decision on a plan allowing oil and gas companies to drill some 4,400 more natural gas wells on the 200,000-acre Anticline.

Local residents opposed to the intense drilling have expressed concern about water and air pollution from the activity.

Linda Baker, community organizer for the Upper Green River Coalition, noted Tuesday that the discovery of pollution in the livestock water well follows the discovery of benzene in more than 80 industrial water supply wells in the area last year. Benzene is a hydrocarbon that can be harmful to human health.

"The problem is that if you're not in the town of Pinedale, anyone in the county gets their water from their own domestic water well," Baker said.

Baker said she regards the water pollution in the area as "a very dangerous situation that the BLM has not even begun to address as they consider approving 4,400 more wells."

The state hasn't determined the source of the hydrocarbons found in the livestock water well, but the nearby oil and gas drilling is a likely suspect, according to Mark Thiesse, hydrogeologist with the state Department of Environmental Quality.

However, Thiesse said subsequent tests have found barely measurable traces of the pollutant, making it difficult to identify a source definitively.

"We're certainly keeping an eye on it," Thiesse said. "And we're trying to figure out where these low levels are coming from, and we keep sampling a variety of wells just to try to get a feel for how widespread the problem is and is there really a health risk to humans or to critters or the environment out there. And so far we're not really finding any significant risk."

Some 250 water wells within a half mile of Anticline drilling must be tested routinely for any change in water quality, he said.

Most of the wells are on the drilling site and are used by the industry in their drilling operations. It's not unusual to find traces of hydrocarbons in such industrial wells.

The pollution found in the stock well was discovered in August, Otto said.