Calling for greater regulation while also acknowledging the benefits of natural gas to coal puts Moniz in league with many of the largest environmental groups, including the Natural Resources Defense Council.
"We think it can be" developed safely, Mark Brownstein, chief counsel for natural gas at Environmental Defense Fund, a New York-based group, said in an interview. "But the jury is out if it is at the moment."
Critics say fracking is fouling water supplies in communities from Pennsylvania to North Dakota and replacing one fossil fuel, coal, with another. Food & Water Watch, a Washington-based environmental group, has circulated a petition against Moniz's nomination.
Thinking of natural gas as a bridge to cleaner energy is a mistake, said Michael Brune, president of the Sierra Club. "We don't think natural gas allows for increased use of renewable energy," Brune said in an interview. "We should use as little of it as we can."
So far, supporting natural gas and nuclear power is a political winner for Moniz: Alaska Sen. Lisa Murkowski, the top Republican on the Energy and Natural Resources Committee, cited those two positions as a reason she should be able work with him, spokesman Robert Dillon said.
In addition to Moniz and McCarthy, Obama has nominated Sally Jewell, the chief executive officer of outdoor retailer Recreational Equipment, as Interior secretary. Jewell has also pushed for measures to combat climate change and advocated for a tax on emissions that would prod companies into making better environmental decisions and shift electricity production away from coal. Jewell will have her nomination hearing before the committee this week. Moniz and McCarthy also must be confirmed by the Senate before taking their posts.
McCarthy, 58, is a Boston native who worked for then-Massachusetts Gov. Mitt Romney as an environmental adviser and later as head of the Connecticut Department of Environmental Protection. She currently leads the EPA's Office of Air and Radiation, which during Obama's first term issued broad regulations to cut pollution from coal-fired power plants and automobiles.
"Truly historic standards have been taken under her watch," Gene Karpinski, president of the League of Conservation Voters, told reporters Monday. That group joined with Intel Corp. and ethanol producers to begin rallying support for her confirmation, a battle that may be tougher than that for Moniz. Girding for battle, they launched the website standwithgina.com.
She also issued the first-ever greenhouse-gas proposal for new electric power plants, rules that the agency is set to finalize this month. Under that rule, no new coal-fired power plants could be constructed without expensive carbon-capture technology, systems that companies say are not commercially available now. New natural gas plants would qualify under those rules, because gas emits about half the carbon dioxide as coal when burned for electricity.
Next up are the rules existing plants, a plan that analysts say could have the largest impact on climate change of any action Obama could take on his own. Those rules could put further pressure on coal plants, even if it isn't set at the same level.
"Clean Air Act rules are key drivers for increased natural gas demand," said John Hanger, the former top environmental official in Pennsylvania. "The biggest problem natural gas faces now is too little demand," and the regulations would change that, he said.
Coal mining companies and coal-heavy utilities say they hope the EPA will change course if McCarthy takes the helm.
"We hope for a more constructive working relationship with the EPA under her leadership," Mike Duncan, president of American Coalition for Clean Coal Electricity, said in a statement. "She can put EPA on a more balanced path that recognizes America's continued need for coal."