WASHINGTON – The Environmental Protection Agency asked nine natural gas companies Thursday to voluntarily disclose the chemical components used in a drilling technique called hydraulic fracturing.
The agency said the information is important to its study of the controversial drilling practice, also known as "fracking." Crews inject vast quantities of water, sand and chemicals underground to force open channels in sand and rock formations so oil and natural gas will flow.
The EPA is studying whether the practice affects drinking water and the public health.
Drilling companies have largely sought to protect their chemical formulas, calling them proprietary. Environmentalists are concerned that the chemicals, some of them carcinogens, will taint underground water supplies.
The EPA is taking a new look at fracking as gas drillers swarm to the lucrative Marcellus Shale region in the northeastern United States and blast into other shale formations around the country.
Fracking is exempt from federal regulation. The process is touted as the key to unlocking huge reserves of clean-burning natural gas.
Supporters say the practice is safe, noting that it is done thousands of feet below ground, much deeper than most water sources. They also point out that authorities have yet to link fracking to contaminated drinking water.
The EPA said in March it will study potential human health and water quality threats from fracking.
"By sharing information about the chemicals and methods they are using, these companies will help us make a thorough and efficient review of hydraulic fracturing and determine the best path forward," said EPA Administrator Lisa Jackson. "Natural gas is an important part of our nation's energy future, and it's critical that the extraction of this valuable natural resource does not come at the expense of safe water and healthy communities."
Letters were sent to nine leading national and regional hydraulic fracturing service providers, including Halliburton, Schlumberger and Key Energy Services.
Chris Tucker, a spokesman for Energy In Depth, a Washington-based group that advocates for the energy industry, said the EPA study offers an important opportunity to demonstrate that fracturing technology is safe, efficient and well-regulated by the states.
"If EPA believes it needs specific information to ensure its study draws on the best science and data available, we're hopeful the agency can coordinate with our members to ensure it has everything it needs, and uses that information in an appropriate way," Tucker said.
The EPA requested the information within 30 days and asked the companies to respond within seven days whether they will provide all of the information. If not, EPA said it is prepared to use its legal authority to force the companies to provide the information.
In Pennsylvania, where the Marcellus Shale is being pursued in a modern-day gas rush, state legislators and environmental regulators are pushing for a law to require drilling companies to disclose what's used at the well sites.
"We have broad right to know about the use of chemicals and discharges of any sort into the environment," said John Hanger, Pennsylvania's environmental protection secretary.
Associated Press writer Marc Levy in Harrisburg, Pa., contributed to this report.