Earlier this year, EPA announced that it would conduct a comprehensive research study to investigate the potential adverse impacts that hydraulic fracturing associated with natural gas wells may have on ground and surface water. Amid growing public concerns that groundwater supplies may already be impacted, EPA announced that it will widen its investigation into the adverse effects of hydraulic fracturing. Toward that goal, EPA sent letters to nine companies currently using fracturing and asked that they disclose detailed information about the chemicals contained in fluids being used to open the underground rock formations. Although EPA framed the request as voluntarily, it advised the companies that the agency would use legal means to compel submissions, if necessary