WASHINGTON, Feb. 9 (UPI) -- U.S. environmental regulators said they submitted a draft study on controversial methods used to extract natural gas out of shale formations.
The U.S. Environmental Protection Agency said it submitted its draft proposal on hydraulic fracturing to its international science advisory board. The EPA said it was proposing a study on the "full life span of water in hydraulic fracturing" to better understand the environmental impact of the extraction technique.
The EPA said eight of the nine companies that practice so-called hydraulic fracturing voluntarily handed over information to help the agency examine the controversial practice. It had to subpoena U.S. energy company Halliburton to hand over its records.
Environmental groups claim that chemicals used to release natural gas from certain rock formations are having a negative impact on the quality of drinking water and public health.
The agency said in March that it would study extraction methods using input from the public sector and meetings with major oil and gas producers.
The EPA said it was under a "tight deadline" to release results of its investigation into hydraulic fracturing. The advisory board will review the draft in March.
