Chemicals released into the air when natural gas is produced by hydraulic fracturing may pose a health risk to those living nearby, the Colorado School of Public Health said.
Researchers found potentially toxic airborne chemicals near wells in Garfield County, Colorado, during three years of monitoring, the school said today in a statement. Drilling has expanded in the county, about 180 miles (290 kilometers) west of Denver.
Emissions from the wells include methane and volatile organic compounds that react with heat and sunlight to form ozone, according to Elena Craft, a health scientist with the Environmental Defense Fund who is studying air quality near gas wells in Texas. The U.S. Environmental Protection Agency has proposed rules that would reduce oil and gas well emissions.
“If you’re leaking natural gas, then you’re leaking a number of pollutants including methane and volatile organic chemicals,” Craft said in an interview. “Health implications? That’s the million dollar question.”
Hydraulic fracturing, known as fracking, has enabled oil and gas companies to access fuel trapped in previously impenetrable shale rock, reversing a decline in U.S. gas production. Environmentalists have previously raised concerns about water contamination as a result of chemicals used in fracking.
“It is important to include air pollution in the national dialogue on natural-gas development that has focused largely on water exposures to hydraulic fracturing,” Lisa McKenzie, lead writer of the study and a research associate at the Colorado School of Public Health in Denver, said in the statement.
The research focused on those living about a half mile from the wells and was requested by county officials in response to the rapid expansion of fracking in the state. One operator has proposed drilling 200 wells about 500 feet from homes in Garfield County.
Wells near Battlement Mesa, where the research was conducted, are tapped by injecting millions of gallons of water mixed with sand and chemicals underground. The mixture is withdrawn during the process of completion as wells are readied for production.
“Non-cancer health impacts from air emissions due to natural-gas development is greater for residents living closer to wells,” according to the release. “We also calculated higher cancer risks for residents living nearer to the wells.”
Benzene, a carcinogen, and chemicals that can irritate eyes and cause headaches, sore throats or difficulty breathing, were found in air close to the wells. The study will be published this month in Science of the Total Environment, according to the statement.
The EPA proposal would cut smog-forming emissions by 25 percent through existing technologies that capture escaping gas, the agency said. The rule would also prevent the release of 3.4 million tons of methane, a greenhouse house that’s 20 times more potent than carbon dioxide. That’s equal to taking 11 million passenger cars off the road, the EPA said.
According to the EPA, the rule would also lead to net gain of $30 million a year for drillers who will have more gas to market. Howard Feldman, director of regulatory and scientific affairs for the Washington-based American Petroleum Institute, said drillers are already reducing emissions from the well where it makes economic sense to do so.
“In places where people think its cost effective, they’re putting in those reduced emissions controls already,” Feldman said in an interview. “We think the controls may outweigh the value of the gas your capturing.”
In his Jan. 24 State of the Union address, President Barack Obama said his administration would “take every possible action” to see that gas fracking is done without putting the public’s health or safety at risk. A November report from a task force named by Energy Secretary Steven Chu said that among other steps to reduce the environmental impact of drillers, emissions of air pollutants, ozone precursors, and methane should be reduced “as quickly as practicable.”
The EPA hasn’t tried to count emissions from oil and gas wells since 1993, according to Fred Krupp, president of the Environmental Defense Fund and a member of Chu’s task force. He called EPA’s proposed rule “a critical step.”
“Nobody has really studied the leaks from shale gas yet,” Krupp said in an interview. “We all need to be searching for the data.”
A study in Fort Worth, Texas, released in July found air pollution levels above state limits at five sites, and reported visible emissions at 296 of 388 gas well sites it examined. Fort Worth, with a population of 741,000, is in the Barnett Shale gas field and has more than 1,400 permitted wells in the city limits.
Garfield County is in Colorado’s gas-producing Piceance Basin. The Colorado Department of Public Health and Environment sampled air around some gas wells in 2000, according to a 2002 report. It concluded that concentrations of non-cancer-causing chemicals in Parachute Valley, Colorado, were too low to pose significant health risk and that benzene levels were high enough to merit further study.
The Colorado Department of Public Health and Environment tested gas sites in Garfield County from 2005 to 2007, and found levels of benzene and other pollutants that were high enough to be hazardous. There weren’t enough samples, though, to draw a clear conclusion, according to a white paper by the Colorado School of Public Health that urged more extensive testing.