PITTSBURGH (AP) - A landmark federal study on hydraulic fracturing, or fracking, shows no evidence that chemicals from the natural gas drilling process moved up to contaminate drinking water aquifers at a western Pennsylvania drilling site, the Department of Energy told The Associated Press.
After a year of monitoring, the researchers found that the chemical-laced fluids used to free gas trapped deep below the surface stayed thousands of feet below the shallower areas that supply drinking water, geologist Richard Hammack said.
Although the results are preliminary - the study is still ongoing - they are a boost to a natural gas industry that has fought complaints from environmental groups and property owners who call fracking dangerous.
Drilling fluids tagged with unique markers were injected more than 8,000 feet below the surface, but were not detected in a monitoring zone 3,000 feet higher. That means the potentially dangerous substances stayed about a mile away from drinking water supplies.
Scott Anderson, a drilling expert with the Environment Defense Fund, said the results sound very interesting.
"Very few people think that fracking at significant depths routinely leads to water contamination. But the jury is still out on what the odds are that this might happen in special situations," Anderson said.