The Document and Its Intended Use
This is a technical guide written and used by the Toxicology
Section of the TCEQ for developing Effects Screening Levels (ESLs),
inhalation Reference Values (ReVs), and inhalation Unit Risk
Factors (URFs).
Although this document is primarily written as guidance for the
Toxicology staff, it also documents (largely by reference) the
processes used to develop ESLs, ReVs, and URFs for any interested
person with training in inhalation toxicology and risk
assessment.
The guide is presented in five chapters. Chapter 1 addresses
several fundamental topics, including legal authority and
regulatory use, consideration of cumulative risk, and
oppportunities for public participation. Chapter 1 also describes
how welfare-based ESLs are set, and introduces ReVs and URFs and
their use in calculating health-based ESLs. Chapter 2 discusses
procedures common to derivation of both acute and chronic toxicity
values. Chapter 3 addresses the procedures that are unique to the
derivation of acute ReVs, and Chapter 4 addresses those that are
unique to the derivation of chronic ReVs and URFs. Chapter 5
discusses the treatment of chemical groups and mixtures.
Process for Requesting ESLs
Individuals who would like to request an ESL from the Toxicology
Section should first check the
2007 ESL list to see if the ESL they are requesting is already
available. Be sure to search by Chemical Abstract Service (CAS)
number since many chemicals have synonyms.
If the ESL is not available on the 2007 ESL list, please contact
Dr. Jong-Song Lee (jlee@tceq.state.tx.us or 512-239-1790) to
request an ESL.
Sign up for Announcements about the Air Pollutant Watch List,
the ESL List, and Toxicology
To join the Toxicology Announcement List, please e-mail:
join-tox@listserv.tceq.state.tx.us
Do not put any information in either the subject or message
body.
You will automatically receive an acknowledgment by e-mail
informing you that your request has been received; however, you
must confirm that you wish to be placed on the list. To confirm,
reply to the message.
Once the list administrator has admitted your e-mail address to
the list, you will receive a “welcome” document.
