Fracking chemicals used during oil drilling

The Pennsylvania Department of Environmental Protection soon plans to post on their website the compounds used in hydraulic fracturing fluids. Water and various chemicals including toxins and heavy metals are pumped under high pressure into Marcellus Shale gas wells to fracture the rock and release methane gas. Some of the water returns to the surface. Much of it stays underground. No scientific studies have been done to understand what happens to that water left deep below the surface. We're talking about millions of gallons of water for one well. Some evidence suggests that it could migrate through the fractured rock to pollute drinking water supplies. The return water is also a hazard and must be disposed of safely. Currently, gas drilling companies are exempt from the Clean Water Act. This is another disaster waiting to happen.

For a list of some of the chemicals used, see this pdf.