About Effects Screening Levels (ESLs)
The Toxicology Division is accepting public comments through July 17, 2015 on the following:
- Approaches to Derive Odor-Based Values
- Proposed Odor ESL List
CLICK HERE to view the documents and for information on how to submit comments (Look for the "New" images in the shaded box).
- Guidelines for Developing ESLs, ReVs, and URFs
- What are Effects Screening Levels?
- Download The Latest ESL List (updated 3/17/14)
- Download Previous ESL Lists
- What to Do if a Chemical Is Not on the List
What are Effects Screening Levels?
Effects Screening Levels are screening levels used in TCEQ’s air permitting process to evaluate air dispersion modeling’s predicted impacts. They are used to evaluate the potential for effects to occur as a result of exposure to concentrations of constituents in the air. ESLs are based on data concerning health effects, the potential for odors to be a nuisance, and effects on vegetation. They are not ambient air standards. If predicted airborne levels of a constituent do not exceed the screening level, adverse health or welfare effects are not expected. If predicted ambient levels of constituents in air exceed the screening levels, it does not necessarily indicate a problem but rather triggers a review in more depth.
Both short- and long-term ESLs are listed on the ESL List. “Short-term” generally indicates a one-hour averaging period. Exceptions are noted parenthetically after a constituent name. “Long-term” indicates an annual averaging period.