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The number of new natural gas wells drilled each year in the United States has skyrocketed, from 17,500 in 2000 to a peak of more than 33,000 in 2008. Fracking technology, once used in just a small percentage of wells, has made it possible to get gas out of deeply buried reserves and has become an essential part of drilling almost every new well. At the same time, fracking has opened up vast new reserves in the eastern United States. The wells are now being drilled in heavily populated parts of Louisiana, Pennsylvania and Colorado, and even into urban neighborhoods of Fort Worth.
Alongside the growth in drilling, reports of fouled water, bad odors and health complaints also have increased. In the few places where basic environmental sampling has been done, the results confirm that water and air pollution are present in the same regions where residents say they are getting sick. Last spring, the EPA doubled its estimates of methane gas leaked from drilling equipment and said the amount of methane pollution that billows from fracking operations was 9,000 times higher than researchers had previously thought.
In Colorado, the ATSDR sampled air for pollutants at 14 sites for a 2008 report, including on Susan Wallace-Babb's property. Fifteen contaminants were detected at levels the federal government considers above normal. Among them were the carcinogens benzene, tetrachloroethene and 1,4-dichlorobenzene. The contamination fell below the thresholds for unacceptable cancer risk, but the agency called it cause for concern and suggested that as drilling continued, it could present a possible cancer risk in the future. Even at the time of the sampling, the agency reported, residents could be exposed to large doses of contaminants for brief "peak" periods.
"Since residents may be repeatedly exposed to these peak concentrations of benzene," the ATSDR report said, "the concentrations ... warrant careful monitoring and exposure evaluation."
In Pavillion, Wyo., where residents have complained of nerve damage and loss of sense of taste and smell, EPA superfund investigators found benzene and other hydrocarbons in well water samples, as well as methane gas, metals, and an unusual chemical variant of a compound used in hydraulic fracturing. A health survey conducted there by an environmental group in late 2010 found that 94 percent of respondents complained of health issues they thought were new or connected to the drilling, and 81 percent reported respiratory troubles. The ATSDR, in consultation with the EPA, advised at least 19 families in Pavillion not to drink their water and to ventilate bathrooms when they bathed, in part because volatile organic compounds can become airborne in a shower. But the government stopped short of saying that drilling caused the contamination or their symptoms.
In 2009, an environmental-sciences firm also found widespread air contaminants in Dish, Texas, a small town in the heart of the Barnett Shale just north of Fort Worth. Wolf Eagle Environmental, hired by the town's mayor and local residents, collected readings from seven monitoring stations and detected 16 chemicals, including benzene and other known and suspected carcinogens. Benzene exceeded Texas' exposure standards at three of the stations.
Wilma Subra, the environmental consultant who ran the survey in Pavillion, also surveyed Dish residents about their health. About 60 percent of respondents reported symptoms that would be expected in people exposed to high levels of the chemicals found in the air samples, Subra said.