PITTSBURGH - 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 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.
"This is good news," said Duke University scientist Rob Jackson, who was not involved with the study. He called it a "useful and important approach" to monitoring fracking, but cautioned that the single study doesn't prove that fracking can't pollute, since geology and industry practices vary widely in Pennsylvania and across the nation.
The boom in gas drilling has led to tens of thousands of new wells being drilled in recent years, many in the Marcellus Shale formation that lies under parts of Pennsylvania, New York, Ohio and West Virginia. That's led to major economic benefits but also fears that the chemicals used in the drilling process could spread to water supplies.
The mix of chemicals varies by company and region, and while some are openly listed, the industry has complained that disclosing special formulas could violate trade secrets. Some of the chemicals are toxic and could cause health problems in significant doses, so the lack of full transparency has worried landowners and public health experts.
The study done by the National Energy Technology Laboratory in Pittsburgh marked the first time that a drilling company let government scientists inject special tracers into the fracking fluid and then continue regular monitoring to see whether it spread toward drinking water sources. The research is being done at a drilling site in Greene County, which is southwest of Pittsburgh and adjacent to West Virginia.
Eight new Marcellus Shale horizontal wells were monitored seismically and one was injected with four different man-made tracers at different stages of the fracking process, which involves setting off small explosions to break the rock apart. The scientists also monitored a separate series of older gas wells that are about 3,000 feet above the Marcellus to see if the fracking fluid reached up to them.
The industry and many state and federal regulators have long contended that fracking itself won't contaminate surface drinking water because of the extreme depth of the gas wells. Most are more than a mile underground, while drinking water aquifers are usually within 500 to 1,000 feet of the surface.
Rep. Bill Johnson, R-Marietta, reacted by saying the process appears to be working safely, and urges federal regulators to stay out of it.
"This study further confirms that Ohio doesn't need bureaucrats in Washington telling state officials how to do the job that they have already been doing responsibly for decades," Johnson said. "The federal regulators should stay out the process. Ohio is trying to capitalize on the shale development and bring prosperity to eastern and southeastern Ohio. ... The opportunity for Ohioans to benefit from this sensible development of our resources is a once in a generation opportunity - as long as the federal government stays out of the way."