Fracking, a slang term for hydraulic fracturing, is a method of extracting natural gas from sedimentary rocks by injecting them with pressurized fluid. When the fluid is injected, the resulting pressure cracks open the rocks, or widens existing cracks, which helps to improve the extraction of natural resources like gas. The pressurized fluid consists of water, sand and various chemicals. Commercial hydraulic fracturing began in the late 1940s, though fracturing by other means was in use in the late 1800s.Because it can take millions of gallons of water to frack a single well, water management is a key issue in fracking. The water must be transported to and from the well, and it must be transported to, and cleaned by, a treatment plant before being returned to the water supply. Some of the water used in fracking isn’t treatable and must be disposed of. As a result, fracking is not only an important source of revenue for natural gas companies, but also water management companies that transport and treat the water. Arguments against fracking include the potential negative consequences on the environment and on people who live near fracking sites.  The chemicals used might contaminate the water supplies in surrounding areas, either underground or above ground; and land may no longer be suitable for farming after fracking has occurred on it. As a result, some local governments have partially or totally banned fracking.  Supporters argue that thanks to fracking, it is possible to extract essential resources that would otherwise remain trapped within the earth. Supporters also argue that certain advanced fracking techniques cause minimal to no damage to the environment and that the social benefit of fracking outweighs the cost, as it could improve the economy and infrastructure of areas rich with natural resources.      NatGasCo wants to extract natural gas from the Marcellus Shale formation. It drills a vertical well 7,000 feet below the earth’s surface, then creates a horizontal turnoff inside the well for another 1,000 feet. A special truck pumps 4 million gallons of pressurized fluid into the well, which creates fractures. Natural gas escapes from these fractures, and flows up the well, into storage tanks. It is then transported through pipelines to its destination. Another company that NatGasCo has hired then transports the wastewater away for purification.