Scroll down for additional online resources and references to the statistics in this piece. Also watch My Water's On Fire Tonight on YouTube — a catchy little video about this issue.

495,000 — That’s how many wells produce natural gas in the United States, and the number is (as they say) exploding. What’s more, the Baker Hughes Rig Count, a real-time measure of gas production, reports for August that actively working rigs have increased by 319 in the last year to 1,959.

Roughly 60% of these rigs are designed to hydraulically fracture or frack for natural gas. Unlike rigs of yesteryear, outputting up to 9,000 psi for several-hour stretches, new designs are tougher and parked at wells for longer, more grueling periods: Stronger steel frames, super-duty quintuplex pumps, fully welded supports, and bigger bearings mean some rigs output 2,400 bhp to 13,500 psi for days of multi-hour cycles — horizontally ramming water, chemicals, and proppant sand (increasingly, synthetic bauxites) down holes thousands of feet deep to crack shale and jailbreak precious fuel.

However, fracking is scientifically linked to some incidents of flammable water and chemical contamination. In April, Duke University researchers confirmed what the Sundance documentary called Gasland and others have sensationalized: Well water 1,000 m or less from Pennsylvania and New York fracking sites contains an average of 17 times the normal amount of methane in drinking water — sometimes enough to allow one to set it ablaze. Isotropic analysis confirms that this isn’t common biogenic methane (say, from cows in the next field) but thermogenic methane found deep in Earth’s crust, where fracking takes place. Similarly, EPA studies verify fracking chemical leaks in Wyoming and Colorado.

Energy-company representatives stress that contamination is rare and fracking offers the promise of independence from foreign oil. In fact, fracking was made exempt from federal Safe Drinking Water Act regulations in 2005, so it’s now up to states (many cash strapped) to both permit and police fracking. The FRAC Act — languishing in Congress — would repeal fracking’s Safe-Water exemption. In the mean time, Pennsylvania, Texas, Wyoming, Michigan, and Arkansas have passed laws requiring gas-drilling companies to divulge, in varying degrees of detail, the secret sauce of chemicals used to more effectively coax natural gas from the Earth. Perhaps in contrast, New York is lifting its 2008 moratorium on fracking, and one commissioner underscores that state oil and gas rights trump those of local bans — a suspect idea already asserted in West Virginia courts.

Indeed, what we have here is a problem of odds. It isn’t that all fracking is dangerous; rather, occasional explosions, spills, and earthquakes are simply results of garden-variety human error coupled with significant increases in the inherently unpredictable activity of large-scale blind-hole rock bursting. It’s statistically likely that with the rise in fracking, there will be a small but ecologically significant increase in accidents.

Similarly, the sheer scale of the fracking process requires huge amounts of water — and in my opinion, this is the gravest issue. According to Chesapeake Energy of Oklahoma City, between 65,000 and 600,000 gallons of water are used in the initial vertical drill of a well; an average of 4.5 million more gallons are used for each fracking session; one well can be fracked many times. Do the math. Though frack water is often reused repeatedly for more fracking, remaining water must either be dumped, left in the ground, industrially filtered, or hauled to other locations willing to accept and store industrial wastewater and partially evaporated slurries (thanks, Ohio). That adds up to a lot of fouled H20 — and at a time when freshwater distribution and scarcity are already issues, even in many parts of the U.S.

— Elisabeth Eitel

• 65,000 and 600,000 gallons of water are used in the initial vertical drill of a well.

• Compounding the water problem is that (according to the World Health Organization) water scarcity is already a 21st-century issue.

• Download the Duke University contamination study here.

• Check out Baker Huges rig-count map (partially based on information from RigDataof DataWright Corp., Fort Worth) at their website. Also download the BHI RigCount app on iTunes for basic information about drilling in your area.