But a report commissioned by an anti-drilling group concludes that methane migration continues to be a problem in Leroy Township, Bradford County — with no end in sight.
Gas Safety Inc., a Southborough, Mass., company that provides gas leak detection to homeowners and industry, said in a report released to The Associated Press that it found pockets of nearly pure methane a few inches below the soil surface, and detected a large plume of gas in the air.
The report concludes that "fugitive methane" from one or more Marcellus Shale gas wells may be entering faults and fractures deep underground, migrating to the surface, and contaminating residential drinking-water wells.
An official with Chesapeake Energy Corp, the driller at the center of the Leroy Township case, said baseline testing conducted before the gas wells were drilled revealed methane already was in the water.
Environmental Secretary Michael Krancer blamed equipment failure at a Chesapeake gas well for leaking methane into residential water wells and nearby wetlands on May 19.
In a July 12 letter to the Philadelphia-based Clean Air Council — which had commissioned an earlier methane survey by Gas Safety — Krancer said Chesapeake's repair work had been successful, resulting in a "substantial decrease" in methane levels in the water wells and wetlands.
"This situation was immediately grasped by the department and DEP immediately responded," Krancer wrote. "The situation is, and at all times was, under control by DEP. Indeed, at this point in time the situation is for the most part over."
Two weeks later, Gas Safety returned to Leroy Township for a second survey, this one commissioned by environmental activist Don Williams and Damascus Citizens for Sustainability, an anti-drilling group based in the Poconos.
Among the findings: Methane concentrations as high as 94 percent just below the soil surface; an airborne methane plume covering about 1.6 square miles; and bubbling in Towanda Creek.
Environmental scientist Bryce Payne, who co-authored the Gas Safety report, told the AP that gas drilling in the region is almost certainly responsible for the methane that he and other researchers detected during their July 25 visit, though his research was not intended to trace the gas back to a specific well.
"Though the gas is no longer hissing out of the ground, it is clear that at this point the event and the damage to groundwater and the domestic wells it supplies is certainly not over, and there is no foreseeable end in sight," he said.
DEP spokesman Kevin Sunday on Friday defended the accuracy of Krancer's letter.
"The volume of gas coming out of the ground has been reduced substantially," Sunday said. "As Secretary Krancer pointed out in his letter, a letter that is still entirely accurate and that we stand by, we have an active investigation under way to monitor the situation as it unfolds."
Chesapeake spokesman Michael Kehs said Friday that "the incident has been successfully addressed and the current situation is temporary. ... The surface expressions of methane have dramatically abated and are almost gone."
Four years into a natural gas-drilling boom in Pennsylvania's Marcellus Shale rock formation, methane contamination of drinking-water supplies continues to trouble drillers and homeowners, though the state has imposed stricter well-casing standards that are supposed to reduce the incidence of methane migration.
In the Leroy Township case, DEP said methane escaped from the well while Chesapeake was making repairs. The agency determined that four homes were affected.
Leroy Township residents Michael and Nancy Leighton knew they had a problem back in May when water from their well started boiling over the top.
Chesapeake installed a filtration system that removes methane from the well, but the Leightons said they still don't trust it. The retired couple uses their water to bathe, cook and wash dishes — but not to drink. And DEP is still finding explosive levels of methane in the well's head space, Michael Leighton said.
"When is it going to go away? Nobody knows. They have no idea, even the scientists who have been up here," said his wife. "The DEP is up here at least once a week. They know it's not over. I don't know where the secretary got his information from, but they know it's not over."
An odorless, colorless, tasteless gas, methane is commonly found in Pennsylvania groundwater. Sources include swamps, landfills, coal mines and gas wells. Methane is not known to be harmful to ingest, but at high concentrations it's explosive and can lead to asphyxiation.
The Gas Safety report noted an elevated methane level in the air of one of the homes it tested, despite open doors and windows and the presence of a methane treatment system in the basement, "which suggests methane levels may rise further when cool weather returns, doors and windows are closed, and heating systems activated."