This past weekend saw the nationwide opening of a movie, Promised Land, depicting ills caused by deep Marcellus Shale gas drilling and "fracking." It echos problems outlined in a 2010 documentary, Gasland, in which water from kitchen spigots caught fire.

Clearly, the snowballing Marcellus boom in northern West Virginia and Pennsylvania brings some environmental troubles, including congestion on narrow country roads. That's common when extractive industries skyrocket.

Meanwhile, the surge has an upside. Two new reports say West Virginia already has gained more than 10,000 direct and indirect jobs since 2008, thanks to the new wave of horizontal drilling in the Marcellus field.

One study, by the U.S. Chamber of Commerce, predicts that Marcellus employment in the Mountain State could swell to 29,000 by 2020, then double to 58,000 by 2035. It says the boom generated $283 million state and local tax revenue in 2012 -- a bonanza that could reach $884 million by 2020.

If these estimates are correct, gas will overshadow the fading coal industry as the biggest bulwark of the state's economy.

The second report, from The Wall Street Journal, says the gas upsurge is so strong that the Business Development Corporation of the Northern Panhandle bought the surface rights to an abandoned steel plant, just to get industrial storage space to lease to drilling firms.

"It's almost like the wildcat days of Texas when they were discovering oil," said Patrick Ford, the group's director. "If you drive along the Ohio River ... you see a field of white or red pickup trucks outside motels at night, and you see restaurants and gas stations filled up in the morning. It doesn't stop."

This description implies that many of the new workers are out-of-state transients staying in motels -- but we hope the boom also generates a lot of permanent West Virginia jobs.

As the two movies illustrate, nature-lovers fear that deep horizontal drilling and "fracking" will pollute the Mountain State. Their alarms should be heeded. Tight government policing should be enforced to keep ravages to a minimum.

Meanwhile, the Sierra Club and other environment-protectors released a study estimating that West Virginia could gain 19,500 jobs if power utilities were forced to invest more in "energy efficiency" -- a strategy to insulate against heat loss, install low-cost appliances and take other steps to prevent enormous waste of power. The strategy also would cut millions from people's electricity bills.