A research study found benzene and other toxic volatile organic compounds at dangerous levels in some groundwater wells close to Barnett Shale oil and gas wells. The Barnett Shale region is near Dallas and Fort Worth.

"A Comprehensive Analysis of Groundwater Quality in the Barnett Shale Region," was published in the American Chemical Society journal Environmental Science & Technology.

"The University of Texas at Arlington team tested 550 water samples collected from public and private water wells in North Texas' Barnett Shale region over the past three years. It found elevated levels of 10 different metals as well as the presence of 19 different chemicals compounds including so-called BTEX (benzene, toluene, ethyl benzene and xylenes) compounds associated with hydraulic fracturing."

"At least one of the BTEX (benzene, toluene, ethylbenzene and xylene) class of 450 compounds was detected in 381 of 550 collected samples."

The authors noted in the paper: "These data do not necessarily identify UOG (unconventional oil and gas) activities as the source of contamination; however, they do provide a strong impetus for further monitoring and analysis of groundwater quality in this region as many of the compounds we detected are known to be associated with UOG techniques."

http://phys.org/news/2015-06-barnett-shale-area-elevated-contaminan...