 This is Part II of a series. Read Part I here.
The Followup - Case Closed
TCEQ didn't notify Jane of the lab results, and didn't initiate any further actions to try to see whether the dibromoethane pollution was a long-term problem, or just a short-term spike. Nor did they try to see if there might be any other problem substances. The investigation was marked closed on October 5th. On November 2nd, the investigation status was updated to note that no violations were found.
We asked TCEQ what the decision process is when there is a hit like this that exceeds the long-term comparison level. Here is Manis' reply:
"We first look at the value and assume that it could be real. In this instance, the reported qualified concentration of 0.16 ppbv 1,2-dibromoethane would not be expected to cause odors or short-term adverse health effects since it is well below the short-term AMCV of 0.5 ppbv. When we have compounds that exceed long-term thresholds, we may conduct followup sampling to determine if there is the possibility that the compound is routinely present. It’s important to note that in considering these numbers it is both scientifically inaccurate and ill-advised to compare a short-term air sample to a long-term AMCV. We check operations at the facility to see if normal, expected operations are occurring or if there appears to be an issue that may be causing impacts off-property."
Manis makes a point about being careful with comparing short-term sample results to long-term comparison values. Just because a substance turned up in a 30 minute sample, that doesn't mean the substance is likely to always be present at that amount. It could be higher or lower on average, but for several reasons, the long-term value is likely to be lower than the sample:
- First, given that short term samples are always taken down-wind from the suspected source, and winds typically shift from day to day, hour to hour, your average exposures are more likely to be lower than any short-term sample, because any given site will not be down-wind every day.
- Secondly, samples are often taken very near the suspected source, and not necessarily at receptor locations, that may be further away, allowing for more wind dispersion.
- Third, short-term samples are usually taken in response to a complaint. These complaints are more likely to happen when actual levels are elevated to the point that there are odors or other effects being perceived.
But Manis added another point that we find troubling:
"We also look to see if we would expect the chemical to be emitted from whatever we are monitoring. In the case of 1,2-dibromoethane, the information we have found indicates that this compound is not due to natural gas emissions. "
Although residents complained of odors and frequently complain of health problems in this neighborhood, and the zip code was the target of a DSHS cancer cluster study last year, TCEQ only seems focused on whether a situation can be attributed to a given regulated entity. If dibromoethane or some other toxic substance were present at such excessive levels as the result of a pesticide spill, or an agricultural application, or improper storage, or even a criminal act of sabotage or terrorism, would it be any less dangerous or worthy of investigation?
For what it's worth, we did look back at some previous samples and 1,2, Dibromoethane had not been detected on the 6/23/2010 sample from the same location.
Results Not Yet Public
But even as I write this, the laboratory results are not linked to from the TCEQ complaint tracking website's record of the complaint. Rather they are available only from a special Barnett Shale air quality monitoring page, also administered by TCEQ. The site's test site symbols are color-coded to indicate whether long-term or short-term comparison values were exceeded, but the icon representing this investigation showed gray, the color for "no risk value yet/Survey only samples". TCEQ's website also says the investigation itself (#866481) is not available until approved by management.
 Williams Responds
Williams spokesman Kelly Swan says the compound is a pesticide and is not a byproduct of their natural gas operations. Swan said "One needs to understand other things occurring in that vicinity, such as the road construction, dirtwork associated with it, etc. We have consistently demonstrated that we are protecting air quality in [Flower Mound]." Swan also said we should look at Flower Mound's third quarter 2010 air quality results. We did. Although none of the VOCs is shown to exceed any short-term or long-term ESLs, carbon disulfide results were troubling, as we will discuss in a minute.
 Town of Flower Mound Misses It
On November 12th, the Town of Flower Mound posted a notice on its website regarding TCEQ investigations of the Sam Wilson site, and stated "Three recent ambient air evaluations conducted by the Town near the Wilson site have not resulted in concentrations that exceeded any AMCVs." The problem is that the statement is misleading, even if technically true. The Flower Mound evaluations did find that carbon disulfide exceeded the long-term ESLs at the test sites near Sam Wilson and Bunn in the February study. In the May study, the quantitation limits were higher than the previous study's sample values, so the results were reported "Not Detected" (of course). In the August study, levels came in at 0.74, 0.81, and 0.85, which were a bit below the 1.0 ppbv long-term ESLs for carbon disulfide. The trick is that the statement said AMCVs and not ESLs. Air Monitoring Comparison Values are based on the appropriate ESL or other regulatory or science-based numbers that most closely match to the duration of the sample. Kleinfelder used short-term (1 hour) ESLs for most AMCVs, including carbon disulfide, in comparing to its 24 hour samples.
Complaints and Investigations Continue
WhosPlayin submitted an open records request for the notes and documents related to this and other investigations in the area for September and October. In the month after Jane's complaint, there were eight additional complaints: three for the Sam Wilson unit, two for the Bunn unit, and three for nearby Cummings unit. In two of those cases, the Jerome analyzers picked up hydrogen sulfide readings of 5 ppb. The most common complaints were burning eyes, hydrocarbon and sulfur or rotten smells, difficulty breathing, and headaches.
On October 22nd, investigators went back to Sam Wilson after receiving an email complaint about odors that the complainant had smelled on October 10th, 12 days earlier. Investigators got a TVA reading of 56.1 ppm, close to what they'd found when investigating Jane's complaint from nearly a month earlier. The Jerome analyzer was used this time and picked up 5 ppb of hydrogen sulfide. Once again, a summa canister was filled for a 30 minute sample, and only tested in the laboratory for VOCs. None of them were found to exceed long or short-term ESLs.
Sulfur Compounds Could Be Involved
Although dangerous VOCs such as benzene have gotten the most attention for their carcinogenic effects, the more immediate and annoying effects such as burning eyes, odors, and sore throats or difficulty breathing may be caused in part by sulfur compounds like carbon disulfide, hydrogen sulfide, and carbonyl sulfide.
In previous investigations of air quality in the Barnett Shale, including in Flower Mound, levels of the dangerous chemical carbon disulfide have been found to exceed long-term ESLs. Flower Mound's own air quality studies conducted by Kleinfelder this year have found carbon disulfide. In the 3Q study, Kleinfelder found carbon disulfide levels as high as 2.1 ppb. This is more than twice the long-term ESL of 1.0 ppb and 21% of the short-term ESL of 10 ppb.
The 2Q Kleinfelder study did not have any carbon disulfide hits higher than the reliable detection limits for the compound. In many cases the RDLs for this compound were as high as 8 ppb, meaning that one wouldn't come close to detecting the substance until it were nearly at the short-term ESL.
The 1Q Klienfelder study found a tentatively identified carbon disulfide level of 69 ppb in one sample, but the authors think the ESLs for the compound are set too conservatively, and there is some discussion there about the implications of these numbers:
"To evaluate this [chemical of concern] further, Kleinfelder contacted the TCEQ for more information on the short-term ESL. The TCEQ provided Kleinfelder with a February 8, 2010 interoffice memorandum noting that the carbon disulfide ESLs were currently being reevaluated as the were hundreds of times below similar screening goals set by EPA and other state regulators for residential comparisons. A copy of the TCEQ memorandum is provided in Appendix C*. To aid in further evaluation, Kleinfelder also utilized the TRRP Air RBEL lnh for carbon disulfide of 235 ppbv. Further, the observed carbon disulfide values are well below the U.S. Environmental Protection Agency (EPA) screening criteria of 2,240 ppbv and California EPA of 2,000 ppbv cited by the TCEQ." * Appendix C is pp 73 - 86 in the 1Q study.
It is important to note that the Kleinfelder numbers were obtained using summa canisters. In a similar air quality study earlier this year by the Barnett Shale Energy Education Council (BSEEC), side-by-side samples utilizing both summa canisters and tedlar bags returned quite different results for carbon disulfide. The sulfur compounds react with the metal canister before it can be analyzed in the lab. Even with tedlar bags, the sample shelf life is only about 24 hours, so samples needing to be analyzed for sulfur compounds need to be sent by overnight delivery to the laboratory.
Conclusion
I wish I could wrap all of this up and offer a good conclusion to this story. But the story is still playing out. Residents are still suffering and complaining, and TCEQ is still doing the same old tests, going through the motions, but not really seeming to want to get to the bottom of this.
What I would like to see is for TCEQ, DSHS, the Town of Flower Mound, and Lewisville ISD to sit down together and work on a strategy for figuring some things out:
- Are people really getting sickened or experiencing symptoms? (I believe they are.)
- At what rates are people being sickened? How might that data be collected? How can LISD and the Town help?
- How can that data be analyzed in a scientific manner?
- In light of current testing protocols and methods that have been used so far, what chemicals could be causing these symptoms? What might have been missed?
- How might TCEQ devise a protocol for testing for a wider range of substances, including formaldehyde and reduced sulfur compounds?
- If certain substances are identified, how can the source be identified and abated?
Notice I didn't include the Railroad Commission or the gas operators in the above. I believe they would derail the process by further denial and redirection. The truth is that neither of these hold any duty to public safety or health. TCEQ seems to care a little more, but that is their job. It is still troubling to me that TCEQ's definition of a customer is the owner of the polluting entity, rather than the citizens who it should be protecting.
I wish I had answers for you. Unfortunately the more I dig into this, the more questions I find. I have clues, and some hunches that I'm glad to share as we go along, but I'm mostly interested in facts.
I'll continue to follow the story, and maybe I'll provide a Part III if something changes.
Updated 11/19 - Updated section "Town of Flower Mound Misses It" based on a reader question and Town feedback.
Update 1/11/2011: - The Town of Flower Mound announced today that it would increase its testing to monthly and include tests for formaldehyde and sulfides. This is good news, and I hope it will provide some clarity.
Related Content
- Flower Mound Neighborhood Deals with Air Quality Issues - Part I
- What is Causing Health Symptoms and Issues in Barnett Shale Air?
- Open Letter Questions Air Quality Study Findings on Sulfur Compounds
Keywords
- Investigations |
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