Marcellus shale production studied for radioactive pollution HARRISBURG, Pa., Nov. 5 (UPI) -- A group of oil and gas associations working in the Marcellus shale area in Pennsylvania announced plans to study radioactivity associated with gas extraction. The Marcellus Shale Coalition and the Pennsylvania Independent Oil and Gas Association said they were collaborating on a study of naturally occurring radioactive material associated with hydraulic fracturing, a drilling practice known also as fracking. Energy companies use water laced with trace amounts of potentially harmful chemicals to dislodge oil and natural gas trapped in shale formations. Some of the water associated with fracking may wind contaminated by naturally occurring radioactive material. "This study's sampling plan exhaustively covers the exploration and production process," MCS President David Spigelmyer said in a statement Monday. Its results, and other sources of sound data, will help our industry more fully understand and proactively address this important issue. A report published last week by Public Health England, an executive agency within the British Department of Health, said there was a "low risk" to the public from radioactive material if fracking is done correctly. The U.S. Energy Department said natural gas production from Marcellus shale exceeded 1 trillion cubic feet in 2011, the last year the department gathered data.