Go to the Globe and Mail homepage

Jump to main navigationJump to main content

EPA findings about possible drinking-water contamination in Wyoming come amid growing concerns about whether natural-gas fracking endangers water supplies. (Spencer Platt/Getty Images/Spencer Platt/Getty Images)
EPA findings about possible drinking-water contamination in Wyoming come amid growing concerns about whether natural-gas fracking endangers water supplies. (Spencer Platt/Getty Images/Spencer Platt/Getty Images)


Encana on defensive over groundwater fouled by fracking Add to ...

The U.S. Environmental Protection Agency has discovered drinking water contaminated by hydraulic fracturing in a U.S. natural gas field operated by Encana Corp., a finding that could have serious and far-reaching consequences for industry.

The EPA, in documents released Thursday, flatly contradicts contentions from Encana and the broader industry that its drilling practices in Wyoming are safe and do not harm drinking water. The Calgary-based company, however, continued to state that there is no link between its work and fouled groundwater.

There are considerable stakes to any finding that fracturing, or “fracking,” is a danger to water supplies. Concerns about fracturing have already led to studies and even bans in numerous places, from New York state to Quebec to France.

The use of fracking has spurred a remarkable growth in oil and gas development across the continent, bringing massive new volumes of hydrocarbons surging to the surface from reservoirs once considered impossible to tap.

There are, however, important distinctions between the type of fracking used in new shale gas plays and the Encana field the EPA examined in its new report.

The agency began investigating groundwater in Pavillion, Wyo., three years ago, after local residents reported that some of their drinking water had been fouled with a gasoline-like odour and had become undrinkable. The gas industry has 169 production wells near Pavillion, which sits on a native reservation and has fewer than 200 people.

In a series of studies, which involved sampling dozens of water wells and drilling two of its own test wells, the EPA discovered the strong presence of numerous contaminants – including gasoline, diesel and substances used in fracturing.

Its conclusion, revealed in a draft report released publicly Thursday, states: “Data indicates likely impact to groundwater that can be explained by hydraulic fracturing.”

Levels of potassium and chloride in some areas were 18 times expected levels. According to the EPA, “the formulation of fracture fluid provided for carbon dioxide foam hydraulic fracturing jobs typically consisted of 6-per-cent potassium chloride.”

Other types of synthetic organic compounds, like tert-butyl alcohol – which is not expected to be found naturally in groundwater – were also discovered. Sampling showed the elevated presence of gasoline, diesel, benzene, toluene, ethylbenzene and xylene. Some of those substances matched with materials used in oil and gas work.

Fracking involves pumping huge amounts of water, sand and chemicals under high pressure into wells. That pressure cracks apart deep rocks, allowing oil and gas to flow through the fractures that are created.

Fracking techniques have spurred an energy revolution in the U.S., bringing on such vast new supplies of natural gas that prices have been severely depressed. A subsequent boom in fracking for oil has opened enough new crude output that some now believe North America could displace all OPEC imports with its own production.

The industry has long claimed fracking is safe.

If it is found to be dangerous, however, it could imperil some of the industry’s biggest plans. Shares in several shale gas producers – including Encana, Talisman Energy Inc. and Chesapeake Energy Inc. – all fell about 5 per cent Thursday, although investors said the selloff was largely attributable to broader market malaise. The S&P/TSX energy index fell 2 per cent.

There are important distinctions between the fracking around Pavillion and the fracking used in major new shale oil and gas plays, such as Marcellus, Bakken and Haynesville. In shale plays, industry typically fractures rock from the horizontal leg of deep wells located at depths of one to three kilometres.

In Wyoming, the fracturing happens from vertical wells – an important difference – that are shallower, ranging from a kilometre to 372 metres below the surface. Some water wells in the area go down to 244 metres, creating a relatively close linkage.

In addition, the EPA notes what may be imprudent industry practices. Only two gas wells around Pavillion have “surface casing” – a protective metal sleeve inside a well that is cemented in place to prevent drilling fluids from leaking out – that goes deeper than the deepest water wells. That means almost every gas well has unprotected stretches at depths people draw water from.

The EPA itself, in a news release Thursday, said conditions in Wyoming are “different from those in many other areas of the country.” But in an interview, spokesman Larry Jackson said it’s possible that what’s happened at Pavillion has “commonalities that could result in similar findings elsewhere.”

Report Typo/Error

Follow on Twitter: @nvanderklippe

Next story




Most popular videos »

More from The Globe and Mail

Most popular