This map from the USGS shows the extent of the Marcellus Shale formation that oil and natural gas companies are exploring for drilling.
The Chesapeake Bay Foundation is calling for a comprehensive federal analysis of Marcellus Shale drilling in the six bay watershed states.
The foundation announced Monday that it has filed a petition under the National Environmental Policy Act calling for the analysis. The foundation says the petition was signed by a number of environmental groups. More than 120 businesses, organizations and elected officials have also signed a letter to the president supporting the petition.
The foundation says assessments are under way, but none is comprehensive. The federal government is obligated by law to ensure drilling won't adversely affect human health or the environment.
Hydraulic fracturing uses water and chemicals to break rock formations and free gas. The Marcellus Shale formation runs beneath western Maryland, Pennsylvania, West Virginia, New York and Ohio.
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