USGS retested water samples in Pavillion after questions were raised over the original draft report released in December last year, which linked contaminated drinking water in the town to hydraulic fracturing operations by Canadian gas giant Encana.
Wyoming officials including Governor Matt Mead depicted the Environmental Protection Agency report as insufficient and called for more sampling, more data, and more participation by state regulators.
Encana, which maintains that its operations are not to blame for the contaminated Pavillion water, blasted the December report’s “numerous flaws” and took particular issue with the monitoring wells the EPA used for testing.
On Wednesday, the USGS released the raw data of its findings and a detailed explanation of its methodology, but did not interpret the results.
The USGS reports “are intended to provide additional scientific information to decision makers and all interested parties on the composition of the groundwater represented in the aquifer underlying Pavillion,” David Mott, director of the USGS Wyoming Water Science Centre, said in a statement.
“While USGS did not interpret the data as part of this sampling effort, the raw data results are adding to the body of knowledge to support informed decisions.”
The USGS said it tested water samples at the request of the State of Wyoming and in co-ordination with the EPA. It said not interpreting the data was “consistent with (its) co-operative agreement with Wyoming”.
USGS and EPA data will now be put to a peer review.
An EPA spokeswoman was quoted as saying the latest data are “generally consistent” with the agency’s original findings.
Encana spokesman Doug Hock said the company’s initial take is that “there’s nothing surprising in the data”.
“More important is the fact that USGS only sampled one of the two monitoring wells. This goes to the heart of concerns raised by state and federal agencies, as well as Encana — EPA’s wells are improperly constructed,” Hock added.
He said Encana is working on its own analysis of the data and hoped to have it available by the end of the day Thursday.
Pavillion is one of the main battlegrounds in the fight between environmentalists who say fracking poses an unacceptable risk to public health and oil and gas operators who content the completion method is safe.
EPA’s December draft report pointed out that its findings “are specific to Pavillion, where the fracturing is taking place in and below the drinking water aquifer and in close proximity to drinking water wells”.
Such production conditions “are different from those in many other areas of the country”, the EPA said at the time.