The Colorado Oil & Gas Association and Independent Petroleum Association of America issued statements calling the study “flawed” and “inaccurate.”
The response follows reports of a study by researchers from the University of Colorado-Denver School of Public Health that people living near drilling sites have a greater risk of suffering from cancer and other illnesses.
Lisa McKenzie, the study’s lead author and research associate at the university, analyzed air sample data collected from monitoring stations in Garfield County between 2008 and 2010.
“Our results appear in a peer-reviewed scientific journal that doesn’t have any specific agenda,” McKenzie said. “We used standard EPA methods. Our paper also notes both the strengths and limitations of the data we used.”
McKenzie noted that EPA standards may overestimate risks. But she also said data on some chemicals released during the well development process weren’t available.
“If there had been, then it is entirely possible the risks would have been underestimated,” McKenzie said.
The report will be published in Science of the Total Environment.
Hydraulic fracturing, also known as fracking, involves pumping water and chemicals into a drilled area to release natural gas. McKenzie found toxic chemicals such as benzene, toluene, ethylbenzene and xylene; the Environmental Protection Agency has identified benzene as a known carcinogen.
The oil and gas industry responded by saying researchers collected outdated data and made incorrect assumptions on the time required to drill and complete a well. The report, they said, also inflates cancer risks and fails to control for other variables that could affect air quality.
The Colorado Oil and Gas Association said additional studies were needed. The association said industry representatives and government agencies were collaborating with Colorado State University researchers on a comprehensive air emissions study of Garfield County using state-of-the-art technology.
“Colorado is one of the most aggressive states in regard to air emission regulations and controls of the oil and gas industry,” read a statement issued by the association. “Our industry will continue to work with our communities and stakeholder partners to reduce air emission impacts while providing the economic and energy resources for the state.”