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 still ongoing - they are the first independent look at whether the potentially toxic chemicals pose a threat to people during normal drilling operations. But DOE researchers view the study as just one part of ongoing efforts to examine the impacts of a recent boom in oil and gas exploration, not a final answer about the risks.
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 he 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.
Over the last four years the debate over fracking chemicals has attracted tremendous attention from state and federal agencies, public health experts, and opponents of fracking. Yet while many people have focused on the potential threat from the chemicals, experts have come to believe that more routine aspects of the drilling process are more likely to cause problems. Poor well construction that allows excess gas to escape, spills of chemicals or other fluids that take place at the surface, and disposal of wastewater are all issues of concern.