Before fracking became the subject of a high-stakes national debate, federal agencies appeared to be moving aggressively to study whether the drilling technique was connected to mounting complaints of water pollution and health problems near well sites nationwide.

As some states began to strengthen regulations for fracking, the federal government prepared to issue rules for how wells would be fracked on lands it directly controlled.

The EPA also launched prominent scientific studies in Texas, Wyoming and Pennsylvania, stepping into each case after residents voiced concerns that state environmental agencies had not properly examined problems.

The EPA probe in Pavillion began in 2008 with the aim of determining whether the town's water was safe to drink. The area was first drilled in 1960 and had been the site of extensive natural gas developmentsince the 1990s. Starting at about the same time, residents had complained of physical ailments and said their drinking water -- drawn from wells -- was black and tasted of chemicals.

The EPA conducted four rounds of sampling, first testing the water from more than 40 homes and later drilling two deep wells to test water from layers of earth that chemicals from farming and old oil and gas waste pits were unlikely to reach.

The sampling revealed oil, methane, arsenic, and metals including copper and vanadium -- as well as other compounds -- in shallow water wells. It also detected a trace of an obscure compound linked to materials used in fracking, called 2-butoxyethanol phosphate (2-BEp).

The deep-well tests showed benzene, at 50 times the level that is considered safe for people, as well as phenols -- another dangerous human carcinogen -- acetone, toluene, naphthalene and traces of diesel fuel, which seemed to show that man-made pollutants had found their way deep into the cracks of the earth. In all, EPA detected 13 different compounds in the deep aquifer that it said were often used with hydraulic fracturing processes, including 2-Butoxyethanol, a close relation to the 2-BEp found near the surface.[1]

The agency issued a draft report in 2011 stating that while some of the pollution in the shallow water wells was likely the result of seepage from old waste pits nearby, the array of chemicals found in the deep test wells was "the result of direct mixing of hydraulic fracturing fluids with ground water in the Pavillion gas field."

The report triggered a hailstorm of criticism not only from the drilling industry, but from state oil and gas regulators, who disagreed with the EPA's interpretation of its data. They raised serious questions about the EPA's methodology and the materials they used, postulating that contaminants found in deep-well samples could have been put there by the agency itself in the testing process.

In response, the EPA agreed to more testing and repeatedly extended the comment period on its study, delaying the peer review process.

Agency officials insist their data was correct, but the EPA's decision to withdraw from Pavillion means the peer-review process won't go forward and the findings in the draft report will never become final.

"We stand by what our data said," an EPA spokesperson told ProPublica after the June 20 announcement, "but I do think there is a difference between data and conclusions."

Wyoming officials say they will launch another year-long investigation to reach their own conclusions about Pavillion's water.

Meanwhile, local residents remain suspended in a strange limbo.

While controversy has swirled around the deep well test results -- and critics have hailed the agency's retreat as an admission that it could not defend its science -- the shallow well contamination and waste pits have been all but forgotten.

The Agency for Toxic Substances and Disease Registry, the federal government's main agency for evaluating health risk from pollution, has advised Pavillion residents not to bathe, cook with, or drink the water flowing from their taps. Some have reported worsening health conditions they suspect are related to the pollution. They are being provided temporary drinking water from the state in large cisterns.