US EPA

In August 2013, EPA submitted a revised draft IRIS assessment of trimethylbenzenes to the agency's Science Advisory Board (SAB) and posted this draft on the IRIS website. EPA had previously released a draft of the assessment for public comment, held a public meeting about the draft, and then revised it based on the comments received. The SAB CAAC-Trimethylbenzenes panel will review this draft assessment. Details about the meeting dates, times, and location are available via the Federal Register Notice posted on March 25, 2014. The SAB provided information on how the public can participate in the external peer review meetings, as well as instructions about how to provide comments to the SAB in the notice. Additional information on the "SAB review of trimethylbenzenes" is on the SAB website.

Report Information: The Toxicological Review of Trimethylbenzenes was originally released for a 60-day public comment period on June 29, 2012. [Federal Register Notice Jun 29, 2012] EPA revised the toxicological review in response to the public comments received. EPA has released the revised external review draft trimethylbenzenes assessment and the SAB CAAC is conducting a peer review of the scientific basis supporting the assessment that will appear in the Integrated Risk Information System (IRIS) database. Information regarding the peer review can be found at the "SAB review of trimethylbenzene" website.

U.S. EPA. IRIS Toxicological Review of Trimethylbenzenes (Revised External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-13/171, 2013.

Trimethylbenzenes (TMB) are a mixture of three isomers: 1,2,3-, 1,2,4- and 1,3,5-TMB. TMBs are produced during petroleum refining, and 1,2,4-TMB makes up approximately 40% of a certain petroleum product (the C9 fraction) which is used as a component of gasoline. Because of this, vehicle emissions are a major source of TMBs. Other uses of TMBs include solvents in research and industry, dyestuff intermediate, paint thinner, and as a UV oxidation stabilizer for plastics.

Date	Description
01-Feb 2012	EPA hosted an interagency science consultation meeting on the review of the draft Toxicological Review of Trimethylbenzenes.
02-May 2012	EPA sent an abbreviated version of the toxicological review containing only information on 1,2,3-trimethylbenzene for interagency science consultation at the recommendation of reviewers.
03-Jun 2012	EPA released the external peer review draft of the trimethylbenzenes assessment for public review and comment. Additionally, the interagency science consultation draft, comments from reviewers, and EPA's responses to selected major interagency comments were also released (see "related links"). [Federal Register Notice June 29, 2012]
04-Aug 2013	EPA's Science Advisory Board (SAB) announced a request for nominations for experts to augment the SAB Chemical Assessment Advisory Committee (CAAC) for the review of the EPA's draft IRIS assessment for trimethylbenzenes. [Federal Register Notice Aug 28, 2013](3pp., 210KB, about PDF), and made available the revised external review draft assessment and draft charge to peer reviewers.
07-Jan 2014	EPA's SAB announced a 3-day public peer review meeting for the draft IRIS Toxicological Review of Trimethylbenzenes for Feb 18-20, 2014. [Federal Register Notice Jan 31, 2014]
08-Feb 2014	To provide the public with additional time to prepare, EPA SAB staff office is rescheduling the February 18-20 meeting of the SAB Chemical Assessment Advisory Committee (CAAC). The EPA SAB staff office will announce a new date in the near future.
09-Mar 2014	EPA's SAB Staff Office has announced two meetings for the SAB CAAC-Trimethylbenzenes panel for the review of the draft IRIS assessment of trimethylbenzenes. A public teleconference is scheduled for May 22, 2014. A face-to face panel meeting is scheduled for June 17-19, 2014 in Arlington, VA. [Federal Register Notice Mar 25, 2014]
10-Mar 2014	EPA updated the peer review charge to include a question regarding EPA's assessment revisions and response to public comments.
11-May 2014	EPA's SAB posted the agenda to the public teleconference meeting that will take place on May 22, 2014. See the SAB site for details.

EPA’s SAB will hold two meetings in May and June 2014 for the external peer review of the trimethylbenzenes IRIS assessment. Information on the peer review can be found at the SAB Trimethylbenzenes website. Following external peer review, the assessment will be revised taking into consideration the comments received. It will then undergo a final internal review by EPA, and other federal agencies and the Executive Office of the President. After completing this review it will be posted to the IRIS database.

This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

• IRIS Toxicological Review of Trimethylbenzenes (Revised External Review Draft) (Aug 2013) (PDF)  (161 pp, 2 MB, about PDF)
• Supplemental Information for Trimethylbenzenes (Aug 2013) (PDF)  (284 pp, 10 MB, about PDF)
• Draft NCEA Charge for Reviewers (Aug 2013) Revised Mar 2014 (PDF)  (7 pp, 202 KB, about PDF)
• Review of the IRIS Draft Toxicological Review of Trimethylbenzenes
• Agency Response

If you have a disability and the format of any material on our web pages interferes with your ability to access the information, please reach out to us using the Contact us about IRIS form for assistance. To enable us to respond in a manner most helpful to you, please indicate the nature of the accessibility problem, the web address of the requested material, your preferred format in which you want to receive the material (electronic format (ASCII, etc.), standard print, large print, etc.), and your contact information.

• SAB Project Page for Trimethylbenzenes
• SAB Teleconference Meeting Agenda May 22, 2014
• Final Peer Review Report of the 1995 Koch Industries Study Report (PDF)  (23 pp, 377 KB, about PDF)
• IRIS Toxicological Review of Trimethylbenzenes (External Review Draft)
• IRIS Toxicological Review of Trimethylbenzenes (Interagency Science Consultation Draft)

• SAB FR Notice: Mar 25, 2014
• FR Notice: June 29, 2012

Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2012-0459