TCEQ Issues Revised "Effects Screening Levels" List
Beveridge & Diamond, P.C. - Texas Environmental Update, January 2008
On November 30, 2007, the Toxicology Section of TCEQ’s Chief Engineer’s Office issued a revised list of Effects Screening Levels (“ESLs”). The revision replaces the ESL list that the agency released in 2003. The new list contains revised ESLs for benzene; butoxyethanol; dichloroethylene, 1, 1-; hexane, n-; methyl amyl ketone; pentene, all isomers; pentene, 1-; pentene, c-2; and pentene, t-2. ESLs are ambient air concentration guidelines used to gauge the potential of constituents associated with modification of an existing facility or construction of a new facility to cause adverse health or welfare effects. They are permit review screening tools, the exceedence of which triggers a more in-depth health effects review. “Short-term” ESLs generally have a one-hour averaging period, and “long-term” ESLs have annual averaging period.
TCEQ set the revised ESLs in the newly-issued list pursuant to the protocol that agency issued in November 2006 in the guidance document entitled, Guidelines to Develop Effects Screening Levels, Reference Values, and Unit Risk Factors (RG-442). Using this new protocol, TCEQ increased the short-term (one-hour) ESL for benzene from 75 micrograms per cubic meter (“µg/m3”) to 180 µg/m3, and the long-term (annual) ESL for benzene from 3.0 µg/m3 to 4.5 µg/m3. The current ESL list can be accessed on TCEQ’s website.1
The Toxicology Section is accepting comments through March 17, 2008 on the agency’s proposed Development Support Documents prepared in connection with its current review of the ESLs for the following nine constituents: butene, 1-; butene, 2-; ethylene; formaldehyde; isobutene; styrene; tetrachloroethylene (PCE); texanol; toluene. Review of the ESLs for additional groups of constituents will follow.
For a printable PDF of this article, please click here.
1 http://www.tceq.state.tx.us/implementation/tox/esl/list_main.html#esl_1
