About TCEQ Development Support Documents (DSDs) for Effects Screening Levels (ESLs) and Air Monitoring Comparison Values (AMCVs)
The Toxicology Division Is Accepting Toxicity Information!!
A New Public Comment Period Has Begun Regarding 24-Hour Values!!
A new public comment period has begun for 3 DSDs!!
Files linked from this page are in Portable Document Format (PDF) 
.
(Help with PDF.)
What is a Development Support Document?
A Development Support Document (DSD) summarizes how chemical-specific toxicity values were derived based on RG-442, Guidelines to Develop Effects Screening Levels, Reference Values, and Unit Risk Factors.
When are Proposed and Final DSDs Published?
A proposed DSD is published at the TCEQ web site for a 60-day public review and comment period. After public comments are received, the TS will address and resolve all relevant issues and make scientifically defensible changes to the DSD and toxicity values, if needed.
The final DSDs with a Response to Comments, if applicable, are then published on the TCEQ website. Registrants on the Toxicology Announcement List will be notified by e-mail when proposed or final DSDs are posted.
WHITE PAPER – TCEQ Guidelines to Develop 24-Hour Inhalation Reference Values
The TCEQ is seeking public comments on a White Paper on TCEQ Guidelines to Develop 24-Hour Inhalation Reference Values. This document provides guidelines to develop chemical-specific 24-h reference values (ReVs). It is a supplement to the TCEQ Regulatory Guidance-442 (RG-442), TCEQ Guidelines to Develop Toxicity Factors. Reference Values are used as air monitoring comparison values (AMCVs). The 24-hour Guidelines went through an external peer review, as discussed in the Document Description and Intended Use. The TCEQ is posting these guidelines for a second public comment period.
WHITE PAPER – Updated Recommendations for Animal-To Human Inhalation Dosimetry
The Toxicology Division (TD) of the Texas Commission on Environmental Quality (TCEQ) is amending Section 3.9.1, Default Dosimetry Adjustments for Gases in the October 2012 regulatory guidance document, TCEQ Guidelines to Develop Toxicity Factors (RG-442). This section is being updated to include information on animal-to-human inhalation gas dosimetric adjustments based on recommendations in Advances in Inhalation Gas Dosimetry for Derivation of a Reference Concentration (RfC) and Use in Risk Assessment (USEPA 2012, EPA/600/R-12/044). Please refer to the White Paper for a discussion of the changes.
Current Public Comment Periods
Regarding 24-Hour Values
White Paper on TCEQ Guidelines to Develop 24-Hour Inhalation Reference Values
24-hour Inhalation Reference Values Development Support Documents
1,3-Butadiene
Benzene
Formaldehyde
The public comment period ends on May 6, 2014
Three Proposed DSDs
Ammonia Phenol
* Hexavalent Chromium and Compounds; (Response to Comments)
*Toxicology Excellence for Risk Assessment (TERA) supported the Texas Commission on Environmental Quality (TCEQ) by conducting an external expert peer review as a letter peer review of Section 4.2 (Carcinogenic Potential, Draft March 2013) of the DSD for Hexavalent Chromium. A June 17, 2013 report containing expert panel member comments was prepared by TERA and is available at: http://www.tera.org/Peer/crvi/index.html 
. TCEQ has updated Section 4.2 based on panel member comments and has prepared Responses to Comments, which are attached to the Hexavalent Chromium DSD.
The public comment period ends on May 6th, 2014
Procedure to Submit Comments
Submit comments by e-mail to tox@tceq.texas.gov or by mail (must be received at the TCEQ no later than the respective comment period end dates) to:
Regular mail:
Toxicology Division, MC 168
Texas Commission on Environmental Quality
P.O. Box 13087
Austin, TX 78711-3087
Mail delivery services:
Toxicology Division, MC 168
Texas Commission on Environmental Quality
12100 Park 35 Circle, Bldg. F
Austin, TX 78753
Contact the TCEQ About DSDs and Fact Sheets
Call: 877-992-8370 (toll free) or 512-239-3900
E-mail: tox@tceq.texas.gov
Write: Texas Commission on Environmental Quality
Toxicology Division, MC 168
P.O. Box 13087
Sign Up to Receive ESL List, AMCV List, and Other Related Toxicology Announcements
For instructions on how to join the Toxicology Announcement List, click here.