TCEQ: No Widespread Air Quality Issues in Barnett Shale
January 27, 2010
The Texas Commission on Environmental Quality released the results of its comprehensive air quality testing in the Barnett Shale. TCEQ investigators conducted tests at 94 monitoring sites in North Texas and found no problems at the vast majority of the locations, with only two monitoring sites requiring immediate action and another 19 which registered elevated levels of benzene but none exceeded the maximum level for the tests of 180 ppb.
Overall, TCEQ Chief Toxicologist Dr. Michael Honeycutt said based on the test results, the commission believes there is “no need for widespread alarm” among North Texas residents since the vast majority of the monitors showed volatile organic compounds (VOCs) to be within acceptable levels while the problems were relegated to only a few select locations. Furthermore, Honeycutt and Deputy Director John Sadlier said at the sites where elevated readings were detected, the problems were often times simple things such as valves left open by mistake, and have been easily corrected.
TCEQ tested for more than one hundred VOCs, but focused mostly on benzene, which is a human carcinogen. The TCEQ officials said the results of the testing came as no surprise.
“Nothing here was really anything that surprised us,” Sadlier said in closing. “As a matter of fact, had we not seen the things that we did, I’d have been very surprised. We know that the gas characteristics as we move across this field change; actually the characteristics of the gas change with wells a thousand yards from each other. So we expected to see benzene and we did, but the benzene again is very localized, so we don’t have widespread air quality issues, at least according to the data which we generated in this study. And it’s a pretty wide area that we looked at.”
The two sites which required immediate attention were both located in eastern Wise County and exceeded both the Long and Short Term ESLs for benzene as a result of mechanical problems when tested last fall. The Targa North Texas LP Bryan Compressor Station had a benzene reading of 1,100 ppb while a Devon Energy well had a concentration of 15,000 ppb five feet from the well as a result of an open valve. Both problems were quickly corrected and subsequent TCEQ tests showed the Targa site with a reading of 0.21 ppb and the Devon well at 0.18 ppb, well within acceptable levels. The Short Term ESL maximum for benzene is 180 ppb. To compare ambient air samples to the Long Term ESL limits, you need to collect a minimum of one sample every sixth day for an entire year. In these studies, sampling was conducted for one hour periods; therefore, the sampling results are compared to the Short Term ESL limit of 180 ppb, not the Long Term ESL limit of 1.4 ppb.
The other 19 sites Short Term tests exceeded the Long Term ESL for benzene of 1.4 ppb but were below the Short Term ESL of 180 ppb. TCEQ is working with the owners of these sites to ensure that repairs are made to bring potentially future high benzene levels back into ambient levels. The repairs are being made under TCEQ’s “Find It and Fix It” program and are thus not being cited for violations.
TCEQ plans to install new permanent monitors in DISH in Denton County and near Eagle Mountain Lake in northwest Tarrant County. The commission plans to continue testing and working with the industry to deal with emissions issues and ensure that the air is safe for North Texas residents.
This article was originally posted here.
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