Fracking - also called hydro-fracking or, officially, horizontal drilling coupled with multi-stage hydraulic fracturing - is a relatively new process of natural gas extraction. Here's a step-by-step look:
A well is drilled vertically to the desired depth, then turns ninety degrees and continues horizontally for several thousand feet into the shale believed to contain the trapped natural gas.
A mix of water, sand, and various chemicals is pumped into the well at high pressure in order to create fissures in the shale through which the gas can escape.
Natural gas escapes through the fissures and is drawn back up the well to the surface, where it is processed, refined, and shipped to market.
Wastewater (also called "flowback water" or "produced water") returns to the surface after the fracking process is completed. In Michigan, this water is contained in steel tanks until it can be stored long-term by deep injection in oil and gas waste wells.
Fracking is fundamentally different than traditional gas extraction methods.
Fracking wells go thousands of feet deeper than traditional natural gas wells.
Fracking requires between two and five million gallons of local freshwater per well - up to 100 times more than traditional extraction methods.
Fracking utilizes "fracking fluid," a mix of water, sand, and a cocktail of toxic chemicals. While companies performing fracking have resisted disclosure of the exact contents of the fracking fluid by claiming that this information is proprietary, studies of fracking waste indicate that the fluid contains: formaldehyde, acetic acids, citric acids, and boric acids, among hundreds of other chemical contaminants.