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TCEQ Toxicology

Toxicology is used to help the TCEQ make scientifically sound decisions when developing environmental regulation & policy.

Updated InformationTCEQ Guidelines to Develop Toxicity Factors
Updated InformationThe AMCV List has been updated
Updated InformationThe ESL List has been updated
New InformationPOSITION PAPER: Approaches to Derive Odor-Based Values and Response To Public Comments
New Information2 updated DSDs and 5 finalized DSDs
New InformationThe public comment period for 2 proposed DSDs has begun




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What Is Toxicology?

Toxicology is the study of the adverse effects of chemicals on living organisms. A toxicologist is trained to examine the nature of those effects and assess the probability of their occurrence.

Toxicology is used to help the TCEQ make scientifically sound decisions when developing environmental regulations and policy. TCEQ toxicologists help by identifying chemical hazards, evaluating potential exposures, and assessing risks.

What Do TCEQ Toxicologists Do?

TCEQ toxicologists provide toxicological support for a broad range of agency activities. They assist with stakeholder meetings and drafting rules, as well as making technical recommendations regarding agency permitting, monitoring, and enforcement.

  • Conduct the toxicological evaluations of air permit applications;
  • Develop toxicity factors such as ESLs and AMCVs;
  • Evaluate environmental data collected from the air, water, and soil;
  • Evaluate ambient air monitoring data;
  • Contribute toxicological expertise to agency enforcement and emergency-response activities;
  • Coordinate all agency activities that assess risks to human health;
  • Notify private drinking-water well owners of potential groundwater contamination as required by legislation in Texas Water Code 26.408 also known as House Bill 3030;
  • Stay abreast of environmental-health issues and initiatives emerging nationally; and
  • Review Baseline Risk Assessments and various other remediation-related documents submitted under the Texas Risk Reduction Program and the Risk Reduction Rules for state and federal Superfund sites.

In all areas of responsibility, the division strives to ensure consistency of reviews across the agency.

Special Projects

The TCEQ Toxicology Division has been involved with numerous studies investigating human exposure to airborne toxic chemicals and the potential of these exposures to cause adverse health effects. These studies have been critically important as they have not only led to a greater understanding of air pollution and more knowledgeable decision-making by the TCEQ, but they have also become an invaluable way to address community concerns, since many of these studies were originally requested by citizens.

Studies have been completed in Houston, Midlothian, and the Dallas–Fort Worth area as well as the Corpus Christi and Barnett Shale areas. (The Barnett Shale is a large natural gas reserve encompassing more than 5,000 square miles and covering at least 17 counties in North Texas.)

CLICK HERE for a listing of other special projects


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Toxicology Staff and Contact Information

You may e-mail us at If you wish to reach a particular staff member, please put “Attn:” and the staffer’s name in the subject line.

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