The Marcellus Shale, encompassing 104,000 square miles across Pennsylvania, West Virginia, Ohio, and upstate New York, is the largest source of natural gas in the US.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/hydrofracking-resulting-radioactive-contaminants-wastewater
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/environment-news-network
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/hazardous-waste
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/new-york
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/natural-gas-exploration
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/radioactive-waste
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/united-states-america-us
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-supply
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/drinking-water
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment