The Marcellus Shale lies under parts of Pennsylvania, New York, Ohio and West Virginia. The gas drilling procedure hydraulic fracturing, or fracking, has made it possible to tap into deep reserves of oil and gas but has raised concerns about pollution. Large volumes of water, along with sand and hazardous chemicals, are injected underground to break rock apart and free the oil and gas. Contaminated wastewater from the process can leak from faulty well casings into aquifers, but it's often difficult to trace underground sources of pollution. Some studies also have shown air quality problems around gas wells, while others have indicated no problems.
Regulators contend that water and air pollution problems are rare, but environmental groups and some scientists say there hasn't been enough research on those issues. The industry and many federal and state officials say the practice is safe when done properly.
Sunday said DEP's obligation "is not to regulate private water supplies but to make determinations as to whether drilling impacted a water supply." He also noted that the Association of Public Health Laboratories reviewed the agency lab last year and found it to be well managed. He added that independent studies have shown that many water wells in the state contain some naturally occurring contamination and that the agency issued the largest civil penalty in the history of the state's oil and gas program last year for a contamination case.