New extraction methods, primarily the drilling method known as "fracking," have sparked a global natural-gas boom. In 2011, more gas was produced than in any previous year, and 2012 is on target to set another record. But even this cheap, plentiful, and relatively clean fuel has significant risks, such as water contamination from toxic spills. "Too many wells do have problems, something companies vehemently deny," says Robert B. Jackson, a Duke University scientist studying drilling impacts. (Consider the 8,000-gallon spill caused by fracking at a site in Dimock, Pennsylvania.)

Seventeen environmental groups have petitioned the EPA to require disclosure of chemicals used in fracking under the Toxics Release Inventory, an effective, decades-old program that already applies to most industries (including the coal industry). Likewise, contaminated water generated in fracking can be tightly regulated under the Resource Conservation and Recovery Act and Toxic Substances Control Act. "Our job isn't to promote natural gas – the market is doing that because the stuff is so cheap and abundant," says Fred Krupp, president of the Environmental Defense Fund and an adviser to the Secretary of Energy. "Our job is to protect air and water supplies."