Eight members of Congress, including several representatives of powerful national security committees, have prepared a letter imploring President Obama to press for expanded natural gas exploration and production in the United States -- primarily though the use of an unconventional and contentious technique known as horizontal hydraulic fracturing.

"As members of both political parties and as citizens in support of your call to get serious about a long-term policy for secure and affordable energy," reads the Monday dated letter from the group, comprised of four Republicans and four Democrats, "we urge you and members of your administration to take a leadership role in encouraging the continued development and utilization of our nation's vast natural gas resources by any means necessary, but most specifically, by unconventional shale gas recovery."

Hydraulic fracturing involves the high-pressure injection of a cocktail of water, sand and a variety of chemicals thousands of feet underground to crack open rock formations and stimulate the release of natural gas. Though the process is not new, refinements in the technique -- including the ability to branch horizontally, in multiple directions, through deep-shale layers from a single bore hole -- are touted by the industry, as well as by the authors of Monday's letter, as being safe, tested and capable of unlocking vast and previously unreachable deposits of natural gas.

But a host of environmental and health concerns have been raised in recent years over lax government oversight of the industry and the potential for chemicals and methane to bleed from poorly constructed wells and into surrounding rock formations, eventually contaminating drinking water supplies closer to the surface.

Other concerns have been raised surrounding the vast amounts of water needed to stimulate wells in this way, as well as the production and disposal of potentially toxic wastewater generated in the process. An article published in The New York Times on Sunday also raised serious questions about the economic viability of natural gas exploration in deep shale formations and whether the gas industry is recklessly overstating the potential returns.

The combined controversies have led to a moratorium on such gas exploration in New York, one of several states sitting atop a highly sought-after deep shale formation known as the Marcellus Shale. The Environmental Protection Agency, meanwhile, is in the midst of an expansive study of potential groundwater contamination from hydraulic fracturing, and other federal agencies, including the Department of Energy, are also reviewing the process.

The industry is staunchly opposed to federal oversight of natural gas development, preferring instead to work with state-level regulators. Critics argue that states are overburdened and ill-equipped to ensure the environmental safety of the gas industry and to manage any potential health risks posed by so-called fracking.

The lawmakers' letter refers heavily to a speech made by the president at Georgetown University on March 30, in which he laid out a broad vision for the future of energy development in the United States and emphasized the need for the country to move toward energy independence -- in large part by tapping these new sources of natural gas.

Drawing on these reserves, the authors argue, is vital to the nation's security interests and is in keeping with the spirit of efforts already being undertaken by the State Department through its Global Shale Gas Initiative, a program designed to export American fracking technology and expertise to other nations seeking to develop energy independence of their own. These include several former Soviet satellite nations, such as Lithuania, Poland, Hungary, Slovakia and Bulgaria, which are critically dependent on natural gas supplies from Russia.

"While we are doing this important work abroad," the legislators note, "it would be the height of contradiction to place unwarranted restrictions on both the locations and methods by which we attempt to recover our own 2,552 trillion cubic feet of natural gas in the United States."

Members of the House Armed Services Committee, Select Intelligence Committee, Judiciary Committee, and Homeland Security Committee are among the signatories of the letter, which include Representatives Michael Conaway and Mac Thornberry, both Texas Republicans; Henry Cuellar, a Texas Democrat; Pennsylvania Democrats Mark Critz and Jason Altmire, along with Republican Bill Shuster, also of Pennsylvania; Ohio Democrat Tim Ryan; and Republican Tom Reed of New York.

"We owe it to our citizens, and most importantly, our military," the letter concludes, "to be free of the constraints of having to fight abroad over resources that can be safely recovered here at home."

