[Federal Register Volume 63, Number 107 (Thursday, June 4, 1998)]
[Notices]
[Page 30495]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14848]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6107-2]


Carcinogenic Effects of Benzene: An Update

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.

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SUMMARY: This notice announces the availability of a final report 
titled, Carcinogenic Effects of Benzene: An Update (EPA/600/P-97/001F), 
which was prepared by the U.S. Environmental Protection Agency's (EPA) 
National Center for Environmental Assessment (NCEA) of the Office of 
Research and Development (ORD).

DATES: This document will be available on or about June 15, 1998.

ADDRESSES: The document is available on the Internet at http://
www.epa.gov/ncea. A limited number of paper copies will be available 
from the Center for Environmental Research Information, National Risk 
Management Research Laboratory, U.S. Environmental Protection Agency, 
26 W. Martin Luther King Drive, Cincinnati, OH 45268; telephone: 513-
569-7562; fax: 513-569-7566. If you are requesting a paper copy, please 
provide your name, mailing address, and the document title and number, 
Carcinogenic Effects of Benzene: An Update (EPA/600/P-97/001F).

FOR FURTHER INFORMATION CONTACT: David Bayliss, National Center for 
Environmental Assessment/Washington Office (8623D), U.S. Environmental 
Protection Agency, Washington, D.C. 20460. Telephone: 202-564-3294; 
fax: 202-565-0078; e-mail: [email protected].

SUPPLEMENTARY INFORMATION: This report was developed at the request of 
the Office of Mobile Sources, Office of Air and Radiation, to update 
the current Agency cancer inhalation risk characterization shown on the 
Integrated Risk Information System (IRIS) and in the 1985 assessment, 
Interim Quantitative Cancer Unit Risk Estimates Due to Inhalation of 
Benzene. The major issue addressed in this report involves the 
magnitude of the risk of cancer to humans exposed to low levels of 
benzene. Occupational studies of workers exposed to benzene continue to 
provide the bulk of evidence of benzene's carcinogenicity. Workers are 
exposed at much higher levels than is the general public. This document 
reaffirms that benzene is a ``known'' human carcinogen by all routes of 
exposure. This finding is supported by evidence from epidemiologic 
studies, animal data, and an improved understanding of mechanism(s) of 
action. Human epidemiologic studies of highly exposed occupational 
cohorts have demonstrated that exposure to benzene can cause acute 
nonlymphocytic leukemia and other blood disorders. Additionally, 
changes in blood and bone marrow consistent with hematotoxicity are 
recognized in humans and experimental animals. Currently, there is 
insufficient evidence to reject a linear dose-response curve for 
extrapolation of risk to low exposure levels and so use of a linear 
extrapolation is still recommended. In its earlier assessment, and in 
IRIS, EPA uses a single risk estimate for benzene of 26 per thousand 
per ppm of lifetime inhalation exposure. This update assessment 
recommends a range of risk estimates, that is, 7.1-25 per thousand per 
ppm.
    A draft of this document underwent public comment during July and 
August 1997 and external peer-panel review on July 16, 1997 (62 FR 
35172-35173). These review comments were considered in preparing the 
final document.

    Dated: May 21, 1998.
William H. Farland,
Director, National Center for Environmental Assessment.
[FR Doc. 98-14848 Filed 6-3-98; 8:45 am]
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