The risks and benefits of drilling for natural gas have been so widely discussed over the past year that even if you haven't been following gas drilling closely, you might now be familiar with the word "frack."

For those who aren't, the term is short for hydraulic fracturing, a practice where gas drillers shoot pressurized water mixed with sand and chemicals into a well to release natural gas from the earth. The practice has been around for decades, but it's gained new prominence in the past few years with the growth of horizontal drilling, where drillers mine the earth laterally deep underground. The technique has allowed the expansion of drilling into gas-bearing shales across the country, but it also requires large quantities of fracking fluids, sometimes millions of gallons per well. And it's this mix of water and chemicals that has generated the bulk of the controversy and a series of studies, orders and regulations in 2010 from the federal government and a number of states.

Of particular concern to regulators and public health advocates are the specific chemicals that go into that chemical mixture. The industry has fought disclosure for years and had largely been able to keep well-to-well specifics secret, but that began to change this year. Wyoming updated its oil and gas regulations and, in an effort to fend off potential federal oversight, started requiring drillers to list the name and concentration of each of the chemicals used in each well. In Pennsylvania, where drilling in the region's Marcellus Shale continues to expand, regulators have written similar rules that await final approval by the legislature. In both cases, however, drillers may be able to find exceptions.

Disclosure has been a center of debate on the federal level as well. Both the EPA and the House Energy and Commerce Committee initiated investigations, seeking details from oil-services companies. In November, Halliburton broke from its peers and refused to give the EPA a full list of the chemicals in its fracking fluids. The agency has since subpoenaed the information and continued to design its study, which is set to begin early next year and last into 2012.

But it could be up to Congress whether and to what degree the EPA and other federal agencies ultimately regulate the practice. After Interior Secretary Ken Salazar raised the prospect of requiring chemical disclosure from drillers on federal lands in November, Reps. Joe Barton, R-Texas, and Fred Upton, R-Mich., -- who is the incoming chair of the House Energy and Commerce Committee -- sent Salazar a pointed letter in which they said they feared that a "rush to regulate" fracking would "chill domestic oil and gas development." Although the letter suggests Upton may not continue the more aggressive oversight of his predecessor, a spokeswoman for current committee chair Henry Waxman, D-Calif., said the fracking study will continue after the House switches hands.

The elections brought change in the states as well. As we reported last summer, politicians and the gas industry in New Mexico and Colorado have been pushing to roll back some of the stricter regulations those states enacted in the past few years. Both states' governors-elect had said as candidates that they supported relaxing the rules. In New Mexico, soon-to-be Gov. Susana Martinez indicated she may seek to loosen a rule that requires drillers to use synthetic liners in their waste pits, saying that "unnecessary and burdensome regulations" have costs jobs and impeded growth.

Aside from disclosure, New York is still working out how and when it will allow drilling to begin in its share of the Marcellus Shale, the deep rock formation that has been a bonanza for gas drillers in Pennsylvania and West Virginia. After vetoing a legislative moratorium on fracking, Gov. David Paterson enacted his own limited moratorium this month. The measure bans new permits for drilling in the Marcellus until July 2011, when the state's Department of Environmental Conservation is expected to have drafted a final set of rules outlining how to handle Marcellus drilling.

In the new year, legislators and regulators across the country can look to a recent study that found that more than three out of four Americans support greater disclosure of fracking chemicals and more studies of the practice's environmental impact. The poll, released this month by the Civil Society Institute, found that three in five people had "at least some awareness of fracking as an issue." We'll let you decide how mainstream that really is, but we'll continue watching these developments around the country.