The industry has boomed in recent years, thanks to a stunning expansion of drilling in previously untapped areas because of the use of hydraulic fracturing, or fracking, which injects sand, water and chemicals to break apart rock and free the gas inside.

NPR: EPA Methane Report Further Divides Fracking Camps

Shale gas is natural gas that is trapped inside shale rock and is extracted by using a technology called hydraulic fracturing, where highly pressurized water mixed with sand and chemicals is used to crack open rocks.

FORBES: Will ConocoPhillips Help China Tap Its Shale Gas Reserves?

Even if migration of hydraulic fracturing fluids into water aquifers were possible, hydraulic fracturing fluids are typically 90% water, 9% sand, and less than 1% other compounds, many of which are common household products that appear in foods anyway.

FORBES: The Sierra Club Fails An Environmental Consistency Test

Hydraulic fracturing pumps many thousands of gallons of mainly water and sand, with a few chemicals, at high pressure into tight gas-bearing shale deposits (hardened muds), creating cracks that allow gas to flow back up the well to the surface ( Shale Shock).

FORBES: The Fracking Solution Is A Good Cement Job

Hydraulic fracturing, or fracking, pumps millions of gallons of water mixed with fine sand and chemicals deep into oil and gas wells to crack gas-bearing rock.

WSJ: NY groups claim industry bias in fracking study

Hydraulic fracturing involves the injection of fluid consisting of approximately 99.5% water and sand (the rest consists of common industrial or even household chemicals or materials) through wells constructed with protective casing and cement, into producing shale formations.

FORBES: Why Anti-Fracking Groups Are Shifting Their Story From Water To Air Quality

The ingredients used in hydraulic fracturing include a small dose of chemicals (0.5%) mixed with water and sand (99.5%).

FORBES: EPA's Fracking Hysteria

The company produces premium monocrystalline sand, which is used to improve the recovery of oil and gas during hydraulic fracturing drilling.

WSJ: Stocks Approach Multiyear Highs