The country's push to find clean domestic energy has zeroed in on natural gas, but cases of water contamination have raised serious questions about the primary drilling method being used.
Vast deposits of natural gas, large enough to supply the country for decades, have brought a drilling boom stretching across 31 states. The drilling technique being used, called hydraulic fracturing, shoots water, sand and toxic chemicals into the ground to break up rock and release the gas. The Environmental Protection Agency has declared the process to be safe, but water contamination has been reported in more than a thousand places where drilling is happening. Gas companies, exempt from federal laws protecting water supplies, may conceal the identities of their chemicals as trade secrets, making it difficult to determine the cause of contamination.
This investigative series includes ongoing material on the social, economic, and environmental impacts of natural gas drilling in the United States.