The U.S. House Energy and Commerce Committee is investigating the impact on the environment of hydraulic fracturing-a process used in natural gas drilling. U.S. Rep. Henry Waxman (D-Calif.), the committee chair, sent letters to the chief executive officers of a handful of drilling companies seeking information on the number of wells and the amount of chemicals used in "fracking." The panel announced the investigation in a recent statement.

An industry group, Energy in Depth, issued the following statement in response to Waxman's investigation.

"Hydraulic fracturing is an essential component of producing clean-burning energy in America today, and to the extent the committee's inquiry into this process helps clear up some of the misconceptions that have come to be associated with the technology, it's a study we look forward to contributing to," said Lee Fuller, executive director of Energy in Depth.

Meanwhile, a Pennsylvania House of Representatives resolution seeks for the U.S. Congress to avoid regulatory oversight of drilling for natural gas in the Marcellus Shale in western Pennsylvania. The Marcellus Shale is a sedimentary rock formation that contains largely untapped natural gas reserves. State Rep. Jim Christiana (R-Beaver) sponsored resolution H.R. 609, maintaining that it was partly in response to a newspaper quote attributed to U.S. Sen. Bob Casey, Jr. (D-Pa.).

"He saw that the senator was quoted as saying that Washington should assume at least some regulatory control," said Joe Pistorio, a spokesman for the Pennsylvania House Republican Caucus. "We feel our Department of Environmental Protection and the industry itself will continue to maintain adequate control."

Senator Casey has sponsored S. 1215, which would repeal an hydraulic fracturing exemption from the Safe Drinking Water Act passed by the U.S. Congress in 2005. Casey's bill would also require oil and gas companies to disclose the chemicals used in fracturing operations. The bill awaits action in the U.S. Senate Committee on Environment and Public Works. Nearly identical legislation, H. 2766, is before the U.S. House Committee on Energy and Commerce. No immediate action appears to be planned on either measure.

Federal regulation of fracturing arose during a public hearing on January 20, 2010, by the House Committee on Energy and the Environment, which was held to discuss the pending buyout of Houston-based XTO Energy Inc. (XTO) by ExxonMobil. XTO is an independent natural-gas producer. A clause in the buyout agreement would likely wipe out the deal if fracturing is banned or its use severely restricted.

A spokesperson for the committee said it has scheduled no further hearings on the pending buyout. An Exxon spokesperson said it hopes the buyout will be completed in the spring, after FTC approval.