Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

  • Environmental Topics
  • Laws & Regulations
  • Report a Violation
  • About EPA
Risk Assessment
Contact Us

IRIS Toxicological Review of Trimethylbenzenes (External Review Draft)

On this page:

  • Overview
  • History
  • Downloads
  • Notices/Outreach

Alert
Alert Notice - This site contains archived material(s)

Archive disclaimer
Archived files are provided for reference purposes only. The file was current when produced, but is no longer maintained and may now be outdated. Persons with disabilities having difficulty accessing archived files may contact the Risk Webmaster for assistance. Please use the contact us form if you need additional support.

Abstract

EPA is conducting a peer review of the scientific basis supporting the human health hazard and dose-response assessment of trimethylbenzenes that will appear in the Integrated Risk Information System (IRIS) database.
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.

Impact/Purpose

EPA is reassessing its IRIS toxicological review of Trimethylbenzenes (1,2,3-;1,2,4-;1,3,5-). This trimethylbenzene reassessment consists of an oral reference dose (RfD), an inhalation reference concentration (RfC), an inhalation unit risk (IUR) and a cancer weight of evidence descriptor. This is the first assessment developing an RfC or IUR for this compound. This assessment is intended to provide human health data to support agency regulatory decisions.

Status

Following external peer review and public comment, 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 White House offices. After completing the review it will be posted to the IRIS database.

Citation

U.S. EPA. IRIS Toxicological Review of Trimethylbenzenes (External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/012Aa-Ab, 2012.

History/Chronology

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. [Federal Register Notice June 29, 2012]

Download(s)

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 (External Review Draft) (PDF)  (138  pp, 1.9 MB, about PDF)
  • Supplemental Information for Trimethylbenzenes (External Review Draft) (PDF)  (220  pp, 9.3 MB, about PDF)
  • Draft Charge to External Peer Reviewers (PDF)  (6  pp, 213.9 KB, about PDF)

Related Link(s)

  • IRIS Toxicological Review of Trimethylbenzenes (Interagency Science Consultation Draft)

Notices

Docket

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

Federal Register Notices

  • FR Notice: Jun 29, 2012
  • Risk Assessment Home
  • About Risk Assessment
  • Risk Recent Additions
  • Human Health Risk Assessment
  • Ecological Risk Assessment
  • Risk Advanced Search
    • Risk Publications
  • Risk Assessment Guidance
  • Risk Tools and Databases
  • Superfund Risk Assessment
  • Where you live
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on December 06, 2016
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshots
  • Grants
  • No FEAR Act Data
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Open Government
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions

Follow.