Under President Bush and Vice President Cheney, fracking was exempted from significant EPA regulation

Hydraulic fracturing, an increasingly common aspect of the oil and gas production process, is not subject to the same standards as other industries when it comes to protecting underground sources of drinking water

Hydraulic fracturing involves the injection of fluids including toxic chemicals into oil or gas wells at very high pressure

Other forms of underground injection are regulated to protect drinking water, but in 2005 Congress created exemptions for hydraulic fracturing to benefit Halliburton and other oil and gas companies

The Safe Drinking Water Act excludes Fracking

See it in the ENERGY POLICY ACT OF 2005.  Go to Page 102, Section 322. HYDRAULIC FRACTURING.

SEC. 322. HYDRAULIC FRACTURING.
Paragraph (1) of section 1421(d) of the Safe Drinking Water Act (42 U.S.C. 300h(d)) is amended to read as follows:
‘‘(1) UNDERGROUND INJECTION.—The term ‘underground injection’—
‘‘(A) means the subsurface emplacement of fluids by well injection; and
‘‘(B) EXCLUDES—
‘‘(i) the underground injection of natural gas for purposes of storage; and
‘‘(ii) the underground injection of fluids or propping agents (other than diesel fuels) pursuant to hydraulic fracturing operations related to oil, gas, or geothermal production activities.’’

The Clean Water Act changes the definition of pollutant

(6) The term "pollutant" means dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal, and agricultural waste discharged into water. This TERM DOES NOT MEAN (A) "sewage from vessels" within the meaning of section 312 of this Act; or (B) water, gas, or other material which is injected into a well to facilitate production of oil or gas, or water derived in association with oil or gas production and disposed of in a well, if the well used either to facilitate production or for disposal purposes is approved by authority of the State in which the well is located, and if such State determines that such injection or disposal will not result in the degradation of ground or surface water resources.

See it in the Clean Water Act. SEC. 502 [33 U.S.C. 1362] General Definitions

P.S. Halliburton did not live up to its voluntary commitment to frack without diesel fuel anyhow

Despite agreeing to stop using diesel fuel when fracking in this agreeement with the EPA, between 2005 and 2007, Halliburton used 807,000 gallons of diesel fuel as a fracturing fluid.