Cabot disputed the EPA's finding that the water well of one house had excessive levels of arsenic, a naturally occuring carcinogen. Cabot said none of the four houses had high levels of arsenic. It said the data that EPA cited apparently came from a test of a public water system, unrelated to well-drilling.
Another house had elevated sodium levels, but Cabot said EPA cited data from a 2008 test when the residence had in place a water-softening system, which treats water by adding sodium. Cabot said more recent tests show a range of sodium that is less than the public water the EPA started delivering to the four residents this month by truck.
"Based on this re-examination, it appears that EPA selectively chose data on substances it was concerned about in order to reach a result it had predetermined," the company said in a statement posted Tuesday on its website.
Terri White, a spokeswoman for the EPA's regional office in Philadelphia, said the agency was reviewing Cabot's response and "will respond accordingly."
Cabot's statement raises the stakes in a legal and public-relations battle over Dimock, which anti-drilling activists describe as ground zero in their effort to halt shale-gas development and hydraulic fracturing.
The EPA's intervention in Dimock this month cast doubt on the judgment of the Pennsylvania Department of Environmental Protection, which had cited Cabot for contaminating water wells of 19 Dimock homes three years ago but said the company had met the terms of a 2010 settlement and allowed it to halt water deliveries to residents on Dec. 1.
