Workers replaced a damaged portion of a natural gas well Monday night that had spilled thousands of gallons of chemical-laced water into fields and a stream last week, the well's owner said, and officials said early tests show the spill had little effect on the environment but an investigation is continuing.
Also Monday, the U.S. Environmental Protection Agency announced that it has directed the well owner, Chesapeake Energy Corp., to give information by Tuesday about the discharge, including details on the fluids used in the drilling process, as well as the effects on water, land and air, and any soil sampling data collected in the area before and after the spill.
Such requests are a common fact-finding tool, an EPA spokesman told the Patriot-News of Harrisburg, but this is apparently the first time the agency has made them for the Marcellus Shale, the newspaper reported.
By May 9, federal officials said, they also want to know about the history of drilling at the site, any permits or standards that may have been violated, and whether the well generated any radiological compounds.
"We want a complete accounting of operations at the site to determine our next steps in this incident and to help prevent future releases of this kind," EPA Regional Administrator Shawn M. Garvin said in a statement.
State officials are leading the investigation into what caused Tuesday's equipment failure and the resulting two-day spill.
Chesapeake, which was drilling the Marcellus Shale well in Leroy Township, said in a statement that specialists replaced the damaged wellhead, thus bringing the well under control.
Brian Grove, senior director of corporate development for Chesapeake, told the Patriot-News that a full investigation would be done "to determine the root cause of the failure, evaluate best management practices and make any and all necessary corrections before returning to normal operations."
Results of tests on water samples taken by the state environmental protection department are expected this week, but an agency spokesman said last week that field checks found no cause for concern.
The Marcellus Shale formation lies primarily beneath Pennsylvania, New York, West Virginia and Ohio, with Pennsylvania as the center of activity. More than 2,000 wells were drilled in the state in the past three years and many thousands more are planned.
Drilling a Marcellus Shale well involves pumping millions of gallons of water and sand laced with chemicals down the well bore at high pressure to break up the dense shale rock more than a mile beneath the surface and release the gas trapped inside. The process is known as hydraulic fracturing. Some of that chemical-laced water returns to the surface as a briny stew carrying sulfates, chlorides, metals and naturally occurring radioactivity that the wastewater picks up deep underground.
DEP spokesman Dan Spadoni said last week that the agency had taken water samples from Towanda Creek and a tributary to screen for chlorides, sulfates, arsenic, barium, iron, magnesium and strontium. The DEP also took samples from seven nearby private wells and from the Susquehanna River where Towanda Creek empties into it, about 16 miles from the wells, he said.