When it comes to water from hydrofracking, the question of safety is murky at best.

The Chemical Cocktail of Fracking Fluid

For many folks the big baddie of hydraulic fracturing, also called hydrofracking or fracking, is fracking fluid — the mixture of water, sand, and chemicals that’s injected deep below the surface to fracture the rock and liberate the natural gas. A typical fracking operation uses between one and eight million gallons of water — that’s as much as 12 Olympic-sized pools. In addition to the water the mixture contains a proppant (typically sand) and a mix of chemicals drawn from a list of more than 700 [pdf]. These chemicals generally make up only about 0.5