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TCEQ Toxicology

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

Hot TopicThe public comment period has begun for the Decane, All Isomers proposed DSD
Hot TopicThe Toxicology Division is requesting toxicity information for n-hexane

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Mission Statement:

The Toxicology Division (TD) helps the Texas Commission on Environmental Quality (TCEQ) make scientifically sound decisions by applying toxicological principles when evaluating environmental data, issuing authorizations, developing environmental regulations and making policy decisions.

TCEQ toxicologists identify chemical hazards, evaluate potential exposures, assess human health risks and communicate risk to the general public and stakeholders

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.

Air Monitoring

Air Monitoring Comparison Values (AMCVs)

Air Permitting

Effects Screening Levels (ESLs)

Air Pollutant Watch List (APWL)

Common Questions and Toxicology Responses

Development Support Documents (DSDs)

Federal Topics

Guidance Documents, Positions Paper, and White Papers


A bibliography of papers by written TCEQ toxicologists that have appeared in scientific journals.

Special Projects

Toxicity Data Requests

Learn How To Submit Toxicity Data and what chemicals we are seeking toxicity data on.