The effect on the water supply of hydraulic fracturing, also known as fracking — a method for extracting heretofore hard to reach natural gas reserves — has caught national attention, even inspiring a fiercely critical movie. Now, the Senate Committee on Environment and Public Works is looking into the effect of fracking on the air — and getting an earful from witnesses from organizations on both sides of the debate with long track records in Washington's influence game..

The panel's Clean Air and Nuclear Safety subcommittee held a hearing Tuesday on recently issued Environmental Protection Agency (EPA) performance standards for reducing smog, air toxins and methane, a greenhouse gas. The EPA previously estimated these rules would create a cost savings between $11 million and $19 million by 2015 by turning gas that has been escaping as air pollution into an energy resource that can be sold.

Gina McCarthy, the Assistant Administrator for the Office of Air and Radiation for the EPA was first to testify, reviewing the agency's air quality standards for fracking. The second panel included:

Fred Krupp, president of the Environmental Defense Fund. The Environmental Defense Fund has spent $552,000 lobbying on all of their issues thus far in 2012, according to the Center for Responsive Politics. The Environmental Defense Fund Action PAC raised $59,000 so far this year, according to Influence Explorer.

Darren Smith, Environmental Manager of Devon Energy Corporation, disputed the EPA's estimates on savings likely to be produced by the regulations, calling it "a drastic overestimate of methane emissions from hydraulically fractured natural gas wells."  Devon Energy's PAC has raised $499,000, so far this year, according to Influence Explorer. One of the Oklahoma-based energy firms top recipients: home-state Sen. James Inhofe,  top ranking Republican on the Senate Committee on Environment and Public Works. Inhofe, who is not a member of the subcommittee that held Wednesday's hearing, received $11,000. Most of the sum came from from Devon Energy cofounderJ. Larry Nichols, and his wife, Polly.

Tisha Conoly Schuller president and CEO of the Colorado Oil & Gas Association, talked about how fracking is regulated in her state — a model for the EPA's new regulations. The group spent $20,000 lobbying in 2005 but no longer lobbies at the federal level. Colorado lobbying records, however, show 10 active lobbyists for the association.

Witnesses on Tuesday also included state environmental officials. John V. Corra is the director of the Wyoming Department of Environment Quality and William C. Allison is the director of the Air Pollution Control Division, Colorado Department of Public Health and Environment.

Sen. Kristen Gillibrand, D-N.Y., a state where fracking has prompted intense debate, made a guest appearance to ask about the air and water quality supervision in regards to fracking. Gillibrand is not a member fo the subcommittee that held the hearing but is on the full Environment and Public Works Committee.