Contamination confirmed, but the cause still a mystery
On Aug. 11, 2009, Meeks got in his red 1994 Nissan pickup and drove to Pavillion's community center, a corrugated steel building with bare walls and concrete floors. He took a seat on one of the wooden benches facing a folding table and a projection screen. More than 80 other locals showed up, hoping for a breakthrough: The EPA had announced it was ready to reveal its findings.

With the room quiet and tense, Chavez, the EPA Superfund investigator, started off hesitantly: Of the 39 water samples his team had taken from around Pavillion, 11 were contaminated with chemicals, including some with strong ties to hydraulic fracturing. The EPA found arsenic, methane gas, diesel-fuel-like compounds and metals including copper and vanadium. Of particular concern were compounds called adamantanes -- a natural hydrocarbon found in gas -- and an obscure chemical called 2-butoxyethanol phosphate. 2-BEp is closely related to another substance that is known to be used in fracking solutions and causes reproductive problems in animals. The Meeks well -- the one that was contaminated in 2005 -- contained traces of benzene, toluene, diesel fuel, other petroleum hydrocarbons, bisphenol A (an endocrine-disrupting toxin used in plastics), the adamantanes, and methane. John Fenton's water had methane and bisphenols. And the Lockers' water contained arsenic, methane and metals.

Chavez cautioned that the findings were still tentative. Because the EPA didn't have a complete list of chemicals to work from, it had to go through the exhaustive process of scanning water samples for spikes in unidentified compounds and then running those compounds like fingerprints through a massive criminal database, hoping to find matches in a vast library of unregulated and understudied substances.

EnCana spokesman Randy Teeuwen stood up at the meeting and said, "We are as concerned as you are, and we want to find the source of these compounds, too." The comment drew jeers from the very crowd that had once regarded Meeks with such skepticism.

Jim Van Dorn, who represents Wyoming Rural Water, a nonprofit that advises utilities and private well owners on water management, turned back to Chavez. "If they'd tell us what they were using, then you could go out and test for things and it would make it a lot easier, right?" he shouted.

"Exactly," Chavez shot back.

But Chavez tried to put the information in context. The compounds weren't used exclusively in fracking fluids, he said. Some of them could also be found in common household cleaners. He wanted to temper expectations -- both of environmentalists and the industry -- and keep the relatively small Pavillion project from taking on outsized national significance.

"We're not ever going to say, 'Yeah, we know for sure,' " he says. "Even if we find risks or something ... again, it's Pavillion. It's Wyoming. It's one little small spot that has totally different geology than the Marcellus Shale (back East)."