At least three contaminated water wells near Pavillion, WY, contain hydraulic fracturing (hydrofrac) chemicals used by natural gas drillers, the U.S. Environmental Protection Agency (EPA) said in a preliminary report issued earlier this month.
Traces of other contaminants, including gas, oil and metals, were reportedly found in 11 of 39 wells tested since March in the Wind River Basin area.
Federal officials began testing the Wyoming water wells earlier this year following complaints of water contamination by the area's residents, EPA said.
"Several private property owners (mostly farmers/ranchers) in and around the Pavillion, WY, area have complained about contamination in their private drinking water and stock water wells," said EPA. "Home owners have talked of a strange odor and they allege the odor and ground water contamination's source could be from the nearby oil and gas drilling and production occurring."
EPA scientists began a preliminary assessment last October. A 44-page preliminary report by EPA scientists, issued earlier this month, did not reach a conclusion about the cause of the contamination. However, "oil and gas drilling may be a source," an EPA spokesperson told NGI.. Because it is a preliminary study, there is no "valid (quality assured) locational data currently available."
"There may be an indication of groundwater contamination by oil and gas activities," the report stated. "Many activities in gas well drilling (and) hydraulic fracturing...involve injecting water and other fluids into the well and have the potential to create cross-contamination of aquifers."
EPA scientist Nathan Wiser told ProPublica.com that the results to date point "stronger and stronger to the source being somehow related to the gas development, including, but not necessarily conclusively, hydraulic fracturing itself." Wiser oversees EPA's enforcement for the underground injection control program under the Safe Drinking Water Act (SDWA) in the Rockies.
EPA's findings, Wiser said, "could certainly have a focusing effect on a lot of folks in the Pavillion area as a nexus between hydraulic fracturing and water contamination."
More testing by EPA is scheduled this fall, and a final report is not expected for several months, said the EPA spokesperson. Final test results could point to pesticides that leached into the area aquifer or water supply, or it could be contaminants that were repeatedly flushed down a sink, said the spokesperson.
The study is being conducted under EPA's Superfund program, which traditionally addresses abandoned hazardous waste sites. Superfund, which also funds the clean-up of releases or threatened releases of hazardous substances, gives EPA authorization to identify parties responsible for site contamination and to compel the parties to clean up the sites.
Contaminants found in some of the wells tested included 2-butoyethanol, or 2-BE, a solvent used in gas extraction as well as some household cleaners. 2-BE has been linked to a breakdown in red blood cells, which may damage the kidneys, liver, spleen and bone marrow.
EnCana Corp., which operates nearly 250 wells in the Pavillion area, eliminated 2-BE from its drilling process because of concerns about its health effects, said spokesman Randy Teeuwen. The producer now is working with EPA to identify possible sources of water contamination in the Pavillion area. EnCana also is supplying water to some of the affected residents, EPA said.
Companies are not required to disclose the chemicals they use for drilling because of an exemption attached in 2005 to the SDWA. However, Congress is weighing legislation that would require the disclosure of hydrofracing chemicals (see NGI, June 15).
Responding to concerns about hydrofrac fluids, the Natural Gas Supply Association earlier this month issued a "representative sample" of the additive ingredients that are used in hydrofracing fluids, noting that water and sand make up 99% of the fluids (see related story).
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