The most sweeping review ever of hydraulic fracturing found that it has not caused widespread harm to U.S. drinking water. But the controversial method of extracting oil and gas from underground rocks still poses many threats to water, officials with the Environmental Protection Agency said Thursday.
The EPA’s long-awaited analysis is considered important because it is a nationwide assessment of the risks to water supplies posed by fracking. The intent is to give states and local governments an idea of what pollution and other effects to expect and help them decide how to regulate the growing industry.
The EPA acknowledged "specific instances" around the country where fracking and related activities had polluted or depleted groundwater, drinking wells, and streams. But the agency maintained in its draft assessment that those situations involved a tiny fraction of the more than 25,000 oil and gas wells that are being drilled every year nationwide.
"We found that hydraulic fracturing processes are being carried out in a way that has not led to widespread, systemic impacts on drinking water," says Thomas Burke, science advisor and deputy assistant administrator of EPA’s Office of Research and Development. "The number of documented impacts is fairly low compared to the number of wells."
Burke added that EPA's massive review—which included conducting multiple peer-reviewed studies and analyzing more than 900 other sources of information—was never intended to be a "numerical catalog of all episodes of contamination."
Instead, the agency, which enforces the nation’s water pollution laws, was trying to identify how streams, aquifers, and wells might be vulnerable to fracking—either through contamination from chemicals, wastewater spills or natural gas intrusion, or through the draining of wells or groundwater.
Opponents and supporters of fracking seized on the report, arguing that it backed what each had been claiming for years.
Industry leaders said the review shows that fracking is a secure process that is key to the country's energy future.
“Hydraulic fracturing is being done safely under the strong environmental stewardship of state regulators and industry best practices," the American Petroleum Institute's Erik Milito said in a statement.
But environmental groups, such as the Natural Resources Defense Council, say the review offers "solid scientific analysis" that fracking is poisoning water.
"The report, while limited, shows fracking can and has impacted drinking water sources in many different ways," Amy Mall, NRDC's senior policy analyst for land and wildlife, said in a statement.
More Than 9 Million Americans Near Fracking
Fracking, injecting a mix of water, sand and chemicals into underground rock formations to release oil or gas, has been around for three-quarters of a century. But the boom now covers 25 states, with most wells being drilled in Texas, Colorado, Pennsylvania, and North Dakota.
Between 2000 and 2013, more than 9 million people lived within a mile of a hydraulically fractured well and about 6,800 drinking water supplies were located within 1 mile of a fracking well. And during that period, reports have surfaced in some locations, including Pennsylvania, Louisiana, and Colorado, of wastewater, spills, or other fracking sources polluting or draining water supplies, leaking explosive gases into drinking water systems, or depleting wells.
The controversy recently has led some cities and counties, as well as the state of New York, to ban the practice.
In response to a request from Congress, the EPA examined some individual cases and, Burke says, "followed the water" to determine future vulnerabilities. The major threats posed by fracking, according to the report, included the potential for contamination from well failures, poorly managed wastewater, or chemical spills. The agency also concluded that fracturing rock formations that contained water posed unique risks.
The EPA also said there was a risk that the process could deplete some water supplies. Fracking nationwide used about 44 billion gallons of water each year in 2011 and 2012.
But the agency concedes there wasn’t always enough information available to determine just how much of a problem fracking posed. Drinking water quality data was often insufficient and there have been few long-term studies of fracking.
While Burke says the agency “did not find a specific instance where a well went dry or a stream went dry,” the report cites examples that suggest the picture was less clear.
In 2011 in northwest Louisiana, for example, drinking-water wells in an area overlapping with the Haynesville Shale ran dry, blamed on excessive withdrawals and droughts. But EPA concludes fracking still may have been a contributor.
In northeast Pennsylvania and Colorado, methane gas, sometimes at explosive levels, was found in many drinking water wells or in groundwater. In some cases, EPA determined the gas was natural occurring; in others, the methane was linked to fracking. But the agency was often unable to definitively determine the precise pathway.
“Water pollution from surface leaks and spills during the storage, transport, and disposal of hydraulic fracturing wastewater happen all too frequently,” says Mark Brownstein, vice president for climate and energy at the Environmental Defense Fund.
The EPA study highlights areas needing more research, including how to handle the hundreds of billions of gallons of wastewater produced by fracking. It also urges states, tribes, local communities, and federal lawmakers to use the information to determine how to protect future water supplies. “States play a primary role in regulating most natural gas and oil development,” EPA officials said in a statement.
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