Some of the chemicals commonly used in the fracking process are hydrochloric acid, quaternary ammonium chloride, ammonium persulfate, isopropanol and methanol. Hydraulic fracturing involves the use of dozens or, in some cases, hundreds of chemicals and additives.
Hydraulic fracturing or "fracking" is a process used by oil and natural gas companies to extract resources from underground deposits that were previously too costly to access with standard drilling techniques. The process begins with drilling a deep hole into the ground and inserting a long metal tube into the well. A high-pressure mixture of sand, water and chemicals is injected into the hole through the metal tube to fracture the underlying rock and release the oil or natural gas contained inside.
Hydraulic fracturing has raised environmental concerns because of the large amounts of water and chemicals used in the process. It is estimated that more than 90 percent of the water injected into fracking wells never returns to the surface, which permanently removes it from the water cycle, according to Earthworks. Some of the chemicals that are involved in the process are known to be toxic or carcinogenic to humans,
As of April, 2015, the EPA, under the direction of Congress, is investigating the potential impact of hydraulic fracturing on drinking water supplies. A list of progress reports and findings related to the Hydraulic Fracturing Study are available at EPA.gov.