A review by a University of Texas at Austin researcher highlights the rapid proliferation of gas industry operations in urban areas and questions whether state and federal air pollution regulatory programs are well designed to ensure health and safety. The review recommends increased government monitoring, health impact studies and regulation of air pollution.
The findings by Rachael Rawlins, faculty member in the UT Community and Regional Planning Program in the School of Architecture, were recently published in the Virginia Environmental Law Journal. They were based on a comprehensive review and analysis of air quality monitoring, regulation and health effect studies of hydraulic fracturing on the Barnett Shale in Texas.
The Barnett Shale is home to the most intensive hydraulic fracturing and gas production activities ever undertaken in a densely urbanized area. The Barnett Shale includes the Dallas/Fort Worth area, where thousands of oil and gas wells have been drilled in and around neighborhoods.
During hydraulic fracturing (used in natural gas extraction), pollutants are released from wellheads, flared gas, pipelines, tanks, pits and compressor stations. Combustion byproducts, including diesel emissions, are emitted by equipment used for drilling, fracturing, transportation of materials and dehydrating gas. Volatilizing chemicals are released during drilling, fracturing and maintenance of well pads and equipment.
According to Rawlins, state and federal regulatory programs do not effectively address cumulative emissions in urban areas, the risk of malfunctions in equipment, encroaching land uses, or the potential interactive effects of mixtures of chemicals. Rawlins explains that regulation of toxic pollutants from gas extraction operations is based largely on questions of cost and available technology.
Although the results of stationary monitors are reassuring, there are relatively few stationary monitors. Moreover, she explains, there is uncertainty as to the adequacy of the benchmark values and the scope of chemicals evaluated. Of particular concern, the Environmental Protection Agency has recognized that risk classifications for hazardous air pollutants generally reflect health risks to adults, not to children. There is considerable uncertainty as to the potential interactive effects of mixtures of chemicals.
"If the driving question is the health effects of toxic emissions, studies must be carefully designed to evaluate health effects during time periods and within geographic areas that relate to toxic exposure," Rawlins says.
Residents of the Barnett Shale have reported apparent leaks and equipment malfunctions, some so severe as to warrant evacuation. Residents have also raised health concerns that could be related to air quality including headaches, respiratory problems, itchy and watery eyes and nosebleeds.
Rawlins examines the Texas Department of State Health Service's cancer cluster analysis conducted in response to parents' concerns about seemingly excessive cases of childhood leukemia in the suburban community of Flower Mound. Although the state acknowledged that gas industry emissions include benzene, a carcinogen known to be associated with leukemia, the state dismissed further analysis with a preliminary study after concluding that it was not able to confirm with 99 percent certainty that cancer rates were significantly elevated in Flower Mound, Rawlins writes. Rawlins explains that, even when the state confirmed elevated rates of breast cancer with 99 percent certainty, it was too quick to dismiss the possibility of an association with toxic emissions.
The article reports on a reanalysis of the state's data prepared by UT Austin researchers in collaboration with Dr. Maria Morandi, a faculty affiliate and former research professor from the Center for Environmental Health Sciences at the University of Montana. The reanalysis found, with 95 percent certainty, that rates of childhood leukemia and childhood lymphoma in Flower Mound are significantly higher than expected; there is only a 1 in 20 chance that the difference is random. In science, 95 percent certainty is considered the norm.
In her article, Rawlins:
- urges the development of publically assessable and transparent standards to govern state health effect studies and guide public reporting on scientific findings and statistical analysis
- suggests the Texas Legislature consider transforming the Texas Environmental Health Institute from a "virtual entity" into an agency with sufficient funding, authority and direction to develop a systematic approach to tracking public health in relation to environmental exposure
- encourages Texas to remove regulatory restrictions and support local efforts to identify potential air toxic "hot spots," and consider air quality issues in planning and zoning actions.
"Texas' reactive and ultimately inadequate effort to respond to citizen concerns on the Barnett Shale reflects a continuing need for across-the-board improvement in monitoring, health-based assessment and public communication," concludes Rawlins.
Explore further: Early results from hydraulic fracturing study show no direct link to groundwater contamination