LISTENING to the polarized energy debate in the United States, you might think natural gas was an economic and geopolitical cure-all — or an environmental curse. Too many oil and gas executives behave as if this newly abundant resource, released from underground shale deposits by the combination of horizontal drilling and hydraulic fracturing, has no environmental challenges. Opponents often act as if it has no economic and environmental benefits.

So here’s a reality check. The shale gas boom is indeed lowering energy costs, creating new jobs, boosting domestic manufacturing and delivering some measurable environmental benefits as well. Unlike coal, natural gas produces minuscule amounts of such toxic air pollutants as sulfur dioxide and mercury when burned — so the transition from coal- to natural-gas-fired electricity generation is improving overall air quality, which improves public health. There’s also a potential climate benefit, since natural-gas-fired plants emit roughly half the carbon dioxide of coal-fired ones.

At the same time, opposition to shale gas development is driven by very real instances of localized air and groundwater pollution. Because of intensive shale-gas development, the small town of Pinedale, Wyo., has experienced smog concentrations comparable to those of Los Angeles. The industry asserts that hydraulic fracturing does not contaminate water supplies when fluids are shot at high pressure into shale deposits to release gas. But inspection records in several states show that mistakes or accidents in other phases of the process — poor well construction or surface spills, for example — have done so.

These environmental concerns are having a major impact on public opinion. A poll by the Pew Research Center last fall found that 49 percent of those surveyed opposed the increased use of hydraulic fracturing, while 44 percent supported it. These views are leading communities and even states to keep out the industry. In 2010, New York, one of four states sitting atop an estimated 141 trillion cubic feet of recoverable natural gas in the Marcellus Shale formation, became the first state to impose a moratorium on hydraulic fracturing. Last year in Colorado, four cities voted to prohibit it. If opponents have their way, a statewide measure restricting the process will be on the Colorado ballot this fall.