1,4-Dichlorobenzene

Overview

The U.S. EPA has conducted a peer review of the scientific basis supporting the human health hazard and dose-response assessment of 1,4-dichlorobenzene that will appear on the Integrated Risk Information System (IRIS) database. Peer review is meant to ensure that science is used credibly and appropriately in derivation of the dose-response assessments and toxicological characterization.

[Update 10/12/06] The EPA extended the public comment period and rescheduled the external peer review panel meeting to review selected sections of the EPA National Center for Environmental Assessment (NCEA) final draft document titled, Toxicological Review of Dichlorobenzenes: In Support of Summary Information on the Integrated Risk Information System (IRIS)(EPA/635/R-03/015), regarding the inhalation reference concentration (RfC) and inhalation cancer assessment for 1,4-dichlorobenzene. EPA also changed the format of the external peer review meeting to include both a teleconference and an in-person panel meeting as described in the October 12, 2006 Federal Register Notice.

Background

1,4-Dichlorobenzene is widely used as a space deodorant for toilets and refuse containers, as a moth repellent in moth balls or crystals, and in other pesticide applications. The scope of the current peer review and public comment is limited to the analyses based on a chronic inhalation bioassay of 1,4-dichlorobenzene published in the peer-reviewed literature (Aiso et al., 2005. J Vet Med Sci 67(10):1019-29) that was not included in the February 2004 external peer review draft. Data from Aiso et al. (2005) were used subsequently in the quantitative dose-response assessments for the 1,4-dichlorobenzene RfC and inhalation cancer assessment.

History/Chronology

Date	Description
1994	The current IRIS assessment for 1,4-dichlorobenzene was placed in the IRIS database, and contains an inhalation RfC.
Feb 2004	A reassessment of the potential health effects of dichlorobenzenes has been undertaken. The draft assessment for dichlorobenzenes (including the 1,2-, 1,3-, and 1,4-isomers) was subject to an external peer review and 30-day public comment period (69 FR 4514, January 30, 2004).
2005	An analyses based on a chronic inhalation bioassay of 1,4-dichlorobenzene was published in peer-reviewed literature (Aiso et al., 2005. J Vet Med Sci 67(10):1019-29) but itwas not included in the February 2004 external peer review draft. This study was identified originally as an unpublished study report by the Japan Bioassay Research Center (JBRC, 1995). Data from Aiso et al. (2005) were used subsequently in the quantitative dose-response assessments for the 1,4-dichlorobenzene RfC and inhalation cancer assessment.

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 1,4 - Dichlorobenzene (PDF)  (234  pp, 2.2 MB, about PDF)
• IRIS SUMMARY DOCUMENTS FOR 1,4 - DICHLOROBENZENE (PDF)  (32  pp, 242.2 KB, about PDF)
• Charge to External Reviewers for the IRIS Toxicological Review for 1,4 - Dichlorobenzene (PDF)  (2  pp, 26.4 KB, about PDF)
• CONSOLIDATED COMMENTS FROM THE EXTERNAL PEER REVIEW (FINAL) (PDF)  (18  pp, 521.5 KB, about PDF)

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Document Related Link(s)

• Full Paper: Toxicology to para - Dichlorobenzene (PDF)  (11  pp, 2.0 MB, about PDF)

Federal Register Notices

• FR NOTICE: OCTOBER 12, 2006
• FR NOTICE: AUGUST 11, 2006
• FR NOTICE: JULY 11, 2006