With examining ambient emissions around fracking sites, the researchers also recorded emissions levels in the region
By Matt Mandel, EnergyInDepth
A new study from researchers at the University of Texas at Arlington (UTA) found that ambient emissions in and around hydraulic fracturing (fracking) sites in South Texas’ Eagle Ford Shale are within acceptable limits – with some compounds at levels measuring only a small fraction of the federal standard.
As one of the study authors, Kevin Schug, mentions in the press release:
“We found that ambient BTEX compound emission in and around fracking sites are within the federal mandated acceptable limits for short-term exposure,”
The study, “Point source attribution of ambient contamination events near unconventional oil and gas development”, focused specifically at levels of ambient BTEX, or benzene, toluene, ethyl benzene, and xylene compounds, near fracking sites in the Eagle Ford.
Collecting data from over 12,800 mobile mass spectrometry measurements across 13 counties, the authors determined that while BTEX compounds were registered, the levels were well below federal safety standards.
For example, the Occupational Safety and Health Administration (OSHA) cites 1000 parts-per-billion (ppb) as a permissible exposure limit (PEL) for benzene over an eight hour period. The levels of ambient benzene around the sites tested did not exceed this limit, as the authors note:
“Benzene concentrations did not exceed the 1000 ppb OSHA standard level on any of the six pad sites; however, there were a number of individual measurements above the 500 ppb threshold, particularly on pads 1 and 6.” (p. 386; emphasis added)
The researchers also note that the levels of ambient toluene and xylene also did not exceed the federally mandated limits. In fact, the levels tested were 40 and 100 times less, respectively, than the OSHA and US National Institute for Occupational Safety and Health (NIOSH) limits. According to the study:
“Toluene was found to be the most prevalent air contaminant, though ambient toluene concentrations did not exceed 5000 ppb, which is well below the OSHA PEL and NIOSH REL [recommended exposure limit] of 200,000 and 100,000 ppb, respectively.” (p. 386; emphasis added)
The study continues:
“Similarly, total ambient xylene isomer concentrations did not exceed the NIOSH air quality standard of 100,000 ppb on any of the six pad sites; they were measured to reach a maximum concentration of 1000 ppb.” (p. 386; emphasis added)
In addition to finding that ambient levels of these compounds were well under acceptable limits, the authors also determined that the recorded emissions were not inherent to development process overall. As the authors state:
“The discovery that individual processes are not emitting BTEX into the atmosphere in a systematic and uniform fashion is certainly comforting; however the operation inefficiencies identified from these data are significant within the context of air quality standards.” (p. 385; emphasis added)
“Collectively, the highly variable nature of the findings presented here, in relation to other investigation of air quality in other American shale plays, suggests that mechanical inefficiencies from producing UD [unconventional development] well pad sites, and not necessarily the inherent nature of the complete UD process, results in contamination events that are currently contributing to ambient BTEX levels on a regional scale.” (p. 386-387; emphasis added)
Along with examining ambient emissions around fracking sites, the researchers also recorded emissions levels in the region.
Again however, the emissions levels regionally were well below acceptable levels – benzene levels did not exceed half the federally mandated limit and toluene levels did not exceed even one percent of the OHSA permissible exposure limit. According to the study:
“Air quality measurements collected proximally to producing UD oil wells resulted in detectable BTEX, albeit at lower concentrations than was observed on individual pad sites. While traveling along state highways and local county roads surrounded by active producing oil wells, ambient benzene and toluene concentrations did not exceed 500 and 2000 ppb, respectively,” (p. 386)
Overall, not only does this study show that fracking does not have a significant impact on air quality regionally; it found that the fracking process itself does not pose an inherent health threat with respect to air emissions in the Eagle Ford.
More importantly though, this study shows that emissions in and around fracking sites are well below “federally mandated acceptable limits,” proving yet again that fracking does not pose a credible risk to air quality.