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WASHINGTON (September 8, 2017) —  The U.S. Environmental Protection Agency’s (EPA) mobile laboratory, using the trace atmospheric gas analyzer and commonly called TAGA, is a triple quadrupole mass spectrometer system, extensively monitored the neighborhood adjacent to the Valero refinery in southeast Houston. To date, no levels of targeted toxic chemicals were detected above the Texas TCEQ Air Monitoring Comparison Values (AMCV) short-term screening levels. Copies of the TAGA results are attached.

EPA continues to conduct ambient air monitoring in Houston, and is focusing on an area of potential concern associated with reported air emissions from a Valero facility in Houston to identify the possible source of emissions. EPA has been on-scene conducting real-time air monitoring near the facility and continues to investigate complaints in the area.

EPA conducted an inspection of the Valero facility on Monday, September 5, 2017, confirmed that a tank at the facility did have a leak which occurred on August 26, 2017 from the Hurricane Harvey storm and flooding.  EPA also confirmed Valero had taken action to respond to and repair the leak.  Based on current site conditions including weather, repair actions by Valero, and air monitoring results, EPA's inspection could not confirm the tank was the source of the air release that led to complaints in the area immediately after the storm.  EPA’s air monitoring performed onsite and around the facility on September 5 does not indicate levels of concern for the community. EPA will continue air monitoring for additional sources in the area.

The Trace Atmospheric Gas Analyzer (TAGA) is a self-contained mobile laboratory capable of real-time monitoring and sampling/analysis of outdoor air or emissions. The instrumentation refers both to the analytical instrument and the mobile laboratory built around it. The instrumentation aboard a TAGA mobile laboratory includes: A TAGA mass spectrometer/mass spectrometer (MS/MS), which provides real-time monitoring for many organic and inorganic compounds at the part-per-billion by volume (ppbv) levels or lower.  An Agilent gas chromatograph/mass spectrometer (GC/MS), which analyzes volatile organic compounds at the ppbv level or lower in air samples collected in Tedlar® bags using a loop injection system. A global positioning system (GPS), which supplies accurate, real-time positional data during mobile monitoring or stationary events.