U.S. EPA scientists are defending the methods they used to test a key well in the Pavillion, Wyo., hydraulic fracturing water contamination investigation.
The agency released results Wednesday from a second round of testing done in April. It said those results are consistent with its preliminary December 2011 report finding that there was fracturing fluid in groundwater in the Pavillion area.
The strongest indication of that contamination came from the deeper of two groundwater monitoring wells drilled at the direction of EPA. Listed as "MW02," it accounted for much of the contamination EPA found, including benzene at 49 times EPA's maximum contaminant level.
But the MW02 well has proved troublesome. It is a "low-yield" well, which means it doesn't recharge quickly after water is withdrawn.
Because of that, when the U.S. Geological Survey tried to replicate EPA's findings, it determined that it did not meet USGS standards for sampling (EnergyWire, Sept. 27). USGS said its "standard practice" is to avoid sampling at low-yield wells, "if possible."
Encana, the main driller in the area, jumped on the inconsistency, along with industry groups. They said USGS's decision not to sample the well validated concerns, first voiced by state officials, that EPA's monitoring wells were improperly constructed.
EPA, though, said its rules allow for sampling such low-yield wells, but using different methods.
"Under EPA guidelines, low yield neither constitutes a justification to preclude sampling nor a reason to disregard sample results from a monitoring well," EPA wrote in Wednesday's report.
EPA's report described USGS's practice of not sampling low-yield wells as a "rule of thumb." It also said its samples from the deeper well were tested at a commercial laboratory under contract to USGS.
Encana spokesman Doug Hock rejected EPA's affirmation of its testing methods, saying the agency ignored industry standards.
"EPA has provided no sound scientific evidence that drilling has impacted domestic drinking water wells in the area," Hock said. "Encana didn't put the hydrocarbons there; nature did."
The industry group that criticized EPA's previous report remained unconvinced, saying USGS found other "dramatically" different results than EPA.
"Right now, the only agency that's saying the EPA did a good job in Pavillion is the EPA," said Simon Lomax of Energy in Depth, a public relations campaign of industry groups, primarily the Independent Petroleum Association of America.
At stake is the reputation of gas drilling and hydraulic fracturing, or "fracking."
Some Pavillion-area residents say they began to suspect water contamination in 2005, around the time hydraulic fracturing and other production activity picked up in the area, where drilling has taken place for decades. But they said state officials ignored their concerns. EPA, though, began an investigation under its Superfund authority.
In December, EPA announced its finding that the best explanation for the contamination it found in Pavillion was that hydraulic fracturing chemicals had been released into the groundwater (Greenwire, Dec. 8, 2011).
Though the results were preliminary, and the agency did not find fracturing fluid in the water that residents drink, it punctured the industry refrain that there has never been a documented case of groundwater contamination from fracking. That talking point was used extensively when the industry lobbied successfully to exempt fracturing from the permitting provisions of the Safe Drinking Water Act.
EPA's finding on frack fluids came under furious assault from Wyoming officials, congressional Republicans, and the oil and gas industry. Amid the barrage of criticism, EPA agreed to the further testing.
Agency officials said they did not have enough money to drill more than the two monitoring wells. In comments issued last spring, the Bureau of Land Management, which handles drilling on federal and tribal land in the area, said "much more robust" testing is needed to draw conclusions about contamination in the area.