A sign warns against swimming in a holding lake in Texas, where Fountain Quail Water Management separates and cleans hydrofracking water. Matt Nager / The New York Times

By IAN URBINA
16 April 2011 WASHINGTON — Oil and gas companies injected hundreds of millions of gallons of hazardous or carcinogenic chemicals into wells in more than 13 states from 2005 to 2009, according to an investigation by Congressional Democrats. The chemicals were used by companies during a drilling process known as hydraulic fracturing, or hydrofracking, which involves the high-pressure injection of a mixture of water, sand and chemical additives into rock formations deep underground. The process, which is being used to tap into large reserves of natural gas around the country, opens fissures in the rock to stimulate the release of oil and gas. Hydrofracking has attracted increased scrutiny from lawmakers and environmentalists in part because of fears that the chemicals used during the process can contaminate underground sources of drinking water. “Questions about the safety of hydraulic fracturing persist, which are compounded by the secrecy surrounding the chemicals used in hydraulic fracturing fluids,” said the report, which was written by Representatives Henry A. Waxman of California, Edward J. Markey of Massachusetts and Diana DeGette of Colorado. The report, released late Saturday, also faulted companies for at times “injecting fluids containing chemicals that they themselves cannot identify.” The inquiry over hydrofracking, which was initiated by the House Energy and Commerce Committee when Mr. Waxman led it last year, also found that 14 of the nation’s most active hydraulic fracturing companies used 866 million gallons of hydraulic fracturing products — not including water. More than 650 of these products contained chemicals that are known or possible human carcinogens, regulated under the Safe Drinking Water Act, or are listed as hazardous air pollutants, the report said. A request for comment from the American Petroleum Institute about the report received no reply. …

Chemicals Were Injected Into Wells, Report Says