-----Original Message-----
From: Tony Walker [mailto:TWALKER@tceq.state.tx.us]
Sent: Tuesday, June 08, 2010 11:03 AM
To: Joel Kertok
Cc: Alyssa Taylor
Subject: Health Effects Evaluation of Barnett Shale Dated May 25, 2010

Mr. Kertok,

As we discussed earlier today, TCEQ is committed to continuing our efforts to monitor air quality throughout the Barnett Shale and to respond to the residents of the area. The TCEQ has dedicated a huge amount of time and resources to the question of Barnett Shale air quality as a result of oil and gas operations in the area, and this focus is continuing.

We have learned a great deal from the monitoring that we have conducted throughout the area.  One of the primary lessons learned is the need for additional long-term air monitoring data.  The absence of long-term data leads to a confusing message to the general public and the media.  Simply taking an instantaneous air sample and then trying to draw conclusions about a long-term health concern is a difficult and complex scientific task, and made all the more difficult when dealing with measured amounts of chemicals that are very low. 

We have recently conducted sampling in your county and would like to provide you with some results. There were originally 19 sites of concern and the March monitoring event left us with six sites. Follow-up investigations in April and May of 1020 addressed 2 of the 6. Attached is a memo concerning a health effects evaluation that has been completed for those six sites, 4  of which are located in Parker County.  Please be advised that it is both scientifically inaccurate and ill-advised to compare a short-term air sample to a long-term air monitoring comparison value (AMCV). The long-term AMCV for benzene is 1.4 ppbv.  The samples we are discussing in this memo are short-term samples, so they should be compared to the short-term AMCV of 180 ppbv. While these results in themselves do not indicate an immediate health concern,  TCEQ will conduct additional monitoring and follow-up investigations to ensure that these facilities are operating properly.  

Please contact me at (817) - 588-5902 if you have any questions regarding this matter. You may also contact our Air Section Manager, Ms. Alyssa Taylor at 817-588-5828.

I look forward to working with you in the future on this all important matter.


Tony L. Walker, REM
Regional Director
TCEQ-DFW Office
817-588-5902
twalker@tceq.state.tx.us