` A technique called hydraulic fracturing, orfracking, is now being used to access thesegas deposits. Fracking involves injecting aslurry of water, sand, and chemicaladditives under pressure through a wellbore drilled into the shale. This producesfractures in the rock that allow the gas toflow out into wells.` With the increased use of fracking havecome environmental concerns, includingcontamination of ground water, risks toair quality, and possible mishandling ofwastes associated with the process.