Fracking is a method of extracting oil and natural gas, both of which are fossil fuels, from shale rock. Fracking combines hydraulic fracturing and horizontal drilling. The shale rock is fractured by a combination of water, sand and chemicals delivered at high pressure, which then releases the oil or gas.
As of 2015, a number of concerns have been raised surrounding the environmental hazards associated with fracking. The process of fracking generates a lot of highly contaminated waste water that can contain radioactive materials, poisons and hydrocarbons. Fracking waste water, or flowback liquid, is stored in pits or underground wells at the fracking site to reduce the risk of a hazardous spill.