IRIS

Ethylene oxide

CASRN 75-21-8

Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (2016 Interagency Science Discussion Draft)

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Overview

In December 2016, EPA finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. EPA’s evaluation was reviewed internally by EPA and by other federal agencies and White House Offices in October 2016, before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science discussion materials provided to other agencies, including interagency review drafts of the EPA’s Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide, are posted on this site.

Note: No major science comments were received on the Interagency Science Discussion Draft.

Citation

U.S. EPA. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (2016 Interagency Science Discussion Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-16/284a-b, 2016.

Contact

IRIS Hotline,  Ph:  202-566-1676,  Email: hotline.iris@epa.gov

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Background

Ethylene oxide (EtO) is a gas at room temperature. It is manufactured from ethylene and is a chemical intermediate in the manufacturing of various chemicals. It is also used as a sterilizing agent for medical and dental equipment and as a fumigating agent for spices and certain other items. The highest levels of human exposure are in occupations involving contact with the gas in plants that manufacture or use EtO and in hospitals that sterilize medical equipment. EtO can also be inhaled by residents living near facilities that produce or use EtO or near sterilizing/fumigating facilities.

The DNA-damaging properties of EtO have been studied since the 1940s. EtO is known to be mutagenic in a large number of living organisms, ranging from bacteriophage to mammals, and it also induces chromosome damage. It is carcinogenic in mice and rats, inducing tumors of the lymphohematopoietic system, brain, lung, connective tissue, uterus, and mammary gland. In humans employed in EtO-manufacturing facilities and in sterilizing facilities, there is strong evidence of an increased risk of cancer of the lymphohematopoietic system and of breast cancer in females.

History/Chronology

Date Description
Jun 1985EPA published the Health Assessment Document for Ethylene Oxide (EPA/600/8-84/009F).
Sep 2006EPA released a draft reassessment for a 30-day public comment period. [Federal Register Notice September 22, 2006]
Jan 2007Peer review meeting of the Science Advisory Board (SAB) (public meeting).
Dec 2007EPA’s SAB issued a final report on the review of the draft assessment of EtO.
Jul 2011EPA initiated Final Agency and an Interagency Science Discussion of a revised draft assessment of EtO.
Jun 2012EPA conducted further Agency review of the revised draft assessment of EtO.
Jul 2013EPA revised the draft assessment and released for additional public review and comment. The interagency science discussion draft of the assessment and related comments were also made available. [Federal Register Notice Jul 23, 2013]
Dec 2013EPA hosted an IRIS public science meeting to discuss the draft assessment released for public comment.
Aug 2014EPA submitted the draft assessment (revised in response to public comments) to the SAB for external peer review. [Federal Register Notice Aug 11, 2014]
Nov 2014EPA’s SAB hosted a panel meeting for the SAB Chemical Assessment Advisory Committee (CAAC), augmented for the review of the draft IRIS assessment of EtO.
Aug 2015EPA’s SAB issued a final report on its review of the draft assessment of EtO.
Oct 2016EPA submitted a revised draft for final Agency Review and Interagency Science Discussion.
Dec 2016EPA posted the final Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide to the IRIS database.

Status

Following review by SAB and consideration of public comments received, the Agency revised the draft assessment and sent it back to Final Agency review and Interagency Science Discussion (step 6 of the IRIS process). Once this was done, the carcinogenicity assessment was finalized (step 7 of the IRIS process) and placed in the IRIS database.


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