Natural Gas Pad Fire Under Investigation in Pennsylvania

July 14 (Reuters) - The Pennsylvania Department of Environmental Protection said on Wednesday it is looking into the cause of a July 13 fire at a natural gas well pad in Susquehanna County.

The fire occurred at a separator tank at a site operated by Chesapeake Energy (CHK.N) in Auburn Township, the agency said in a statement.

The tank ignited at approximately 8 p.m. EDT and was extinguished at around 10 p.m. by local emergency responders working with the company.

The well was producing natural gas from the Marcellus Shale formation through a pipeline away from the wellhead to a production unit where a valve failed, leaked natural gas and caught fire.

"Fortunately, this incident does not appear to have caused any significant environmental contamination, thanks to the prompt response efforts of the local emergency responders and the company," DEP Secretary John Hanger said, noting that no injuries or evacuations were reported as a result of the incident.

"We'll be investigating this operation closely to see what can be learned by both the department and gas well operators," Hanger said.

Chesapeake notified the Pennsylvania Emergency Management Agency of the fire at approximately 8:30 p.m.

DEP dispatched an oil and gas inspector immediately to the scene to assess the conditions. The site will remain closed until repairs can be made and DEP completes its investigation.

Chesapeake Energy has been issued 698 permits to develop natural gas in Pennsylvania, 697 of which are located within the Marcellus Shale. The company operates 187 wells in the state, 182 of which are in the Marcellus Shale.

DEP on Tuesday decided to allow EOG Resources (EOG.N) and C.C. Forbes to resume drilling activities in the state after a 40-day suspension due to a well blowout in Clearfield County that allowed natural gas and wastewater to escape from the well uncontrollably for 16 hours.

The Marcellus Shale formation, which stretches across parts of Pennsylvania, New York, Ohio and West Virginia, is estimated to have enough gas to meet total U.S. needs for a decade or more and is drawing the attention of major energy companies as well as groups concerned about possible health risks from controversial drilling techniques. (Reporting by Joe Silha; Editing by Marguerita Choy)