One of the promising sources of natural gas is shale formations. There has been many articles recently claiming our energy problems are solved by shale gas. However this Alternet article points out that shale gas extraction involves piping water into the shale formation. Hydraulic fracturing, or fracking, is a technique that releases natural gas trapped in underground shale formations by injecting water, chemicals, and sand to "frack" the rock structures and release the gas. Often, large quantities of groundwater contaminated by chemicals, radioactive elements, or other minerals are produced in the process. Unless great care is taken, this "produced water" mixed with water used for fracturing can flow to the surface or into groundwater systems and contaminate land, drinking water supplies, and natural waterways. In other words, mining shale gas most likely involves widespread poisoning of water systems.