From the Center for American Progress:

The oil and natural gas lobby is working hard to prevent the Environmental Protection Agency from establishing safeguards to protect the public from chemicals used to produce shale gas through “hydraulic fracturing,” also called “fracking” or “fracing.” Oil and gas companies use fracking in combination with horizontal well drilling; the process involves injecting a mixture of water, sand, and chemicals at high pressure into rock formations thousands of feet below the surface to fracture the rock and allow oil and gas previously trapped inside the rock to escape. Recent advances in drilling techniques combined with fracking have dramatically expanded the supply of technically recoverable shale gas. But studies show that the chemicals may pollute nearby sources of water.

BP, ConocoPhillips, and Shell Oil Co.’s latest lobbying efforts propose. . .[Congress] exempt fracking from federal oversight. . .

The proposal would be on top of a similar fracking loophole already on the books. The practice is currently protected from oversight under the Safe Drinking Water Act due to an exemption in the Energy Policy Act of 2005. The loophole was added into the bill after a 2004 EPA study . . . called “scientifically unsound” by Weston Wilson, an EPA scientist with more than three decades of experience with the agency. The Oil and Gas Accountability Project also reported that, “EPA removed information from earlier drafts that suggested unregulated fracturing poses a threat to human health, and that the Agency did not include information that suggests fracturing fluids may pose a threat to drinking water long after drilling operations are completed.”