Visit our inter­ac­tive news appli­ca­tion — “Shale Play: Nat­ural Gas Drilling in Pennsylvania.”

To cre­ate this news appli­ca­tion, NPR StateIm­pact acquired lists from the Penn­syl­va­nia Depart­ment of Envi­ron­men­tal Pro­tec­tion — the agency charged with per­mit­ting and reg­u­lat­ing oil-and-gas drilling in the Key­stone State.

The agency releases well data semi-annually, so the records in the appli­ca­tion rep­re­sent active wells from July 1, 2011 to Dec. 31, 2011. Gas pro­duc­tion totals and days rep­re­sent activ­ity dur­ing that period. The appli­ca­tion also reflects vio­la­tions reported from Jan. 1, 2009 to Dec. 31, 2011, on any wells that were active dur­ing from July 1, 2011 to Dec. 31, 2011.

The app only tracks pro­duc­ing wells, so the thou­sands of addi­tional wells DEP has issued per­mits for, but aren’t yet pro­duc­ing, do not appear on the site. Finally, a reminder that 2,200 wells doesn’t mean there are 2,200 large drilling rigs dot­ting Penn­syl­va­nia. Energy com­pa­nies drill mul­ti­ple wells on each site.

The wells data are pre­sented largely as released by the depart­ment, though we did omit a hand­ful of dupli­cate records in which wells were assigned sep­a­rate owners.

The vio­la­tions data are pre­sented as released by the depart­ment, so some vio­la­tions appear as dupli­cates because two enforce­ment actions can be asso­ci­ated with one vio­la­tion in the department’s rela­tional data­base. The agency, how­ever, releases a flat dump from the data­base, so these dupli­cates are unavoid­able. Be care­ful if you plan to use the data for well counts or fine totals with­out first sep­a­rat­ing inspec­tions, vio­la­tions and enforce­ments into sep­a­rate tables with dis­tinct records.

Please let us know if you spot errors or have ques­tions about the data.