Methane gas has bubbled to the surface in three residential water wells and two streams in Bradford County, in northeastern Pennsylvania, near a Chesapeake Energy Marcellus Shale gas drilling operation.

The state Department of Environmental Protection said it, along with Chesapeake, is continuing to investigate the source of the methane gas that began showing up in the water wells, two tributaries of Towanda Creek and a nearby wetland in Leroy Township on Tuesday.

Chesapeake's Morse well pad, which has two Marcellus gas wells, is about a half mile from the affected homes, according to a statement issued Thursday by Dan Spadoni, a DEP spokesman.

Mr. Spadoni said DEP Oil and Gas Program staffers collected gas samples at both wells on tuesday for the purposes of running isotopic gas fingerprinting tests. On Wednesday,DEP staff monitored water wells that were bubbling with methane and checked the homes fore methane.

"The investigation is ongoing," he said.

Mr. Spadoni said all three residential wells have been vented and methane monitoring alarms have been installed by Chesapeake. A mobile water treatment unit was set up at one home and a temporary water supply tank, commonly referred to as a "water buffalo," was installed at another. Two homes are receiving bottled water.

Chesapeake did not respond to a request for comment this afternoon, but the DEP said a company consultant is continuing to assess private water wells at the three affected homes as well as other water wells around the Morse well pad.

By Don Hopey: