NEW ORLEANS (AP) — An environmental watchdog group cautions that the nation's boom in cheap natural gas — often viewed as a clean energy source — is spawning a wave of petrochemical plants that, if built, will emit massive amounts of greenhouse gases.

The Washington-based Environmental Integrity Project says hydraulic fracturing of shale rock formations and other advances, such as horizontal drilling, have made natural gas cheap and plentiful — so plentiful that the United States has begun exporting gas.

Thanks to this energy boom, the group calculated that if 44 large-scale petrochemical developments proposed or permitted in 2015 were built they would spew as much pollution as 19 new coal-fired power plants would.

The report says this potential load of pollution needs to be considered in efforts to curb greenhouse gases.

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