home edit2 whole TSD November 2002 PDF format - OEHHA

INTRODUCTION
The Technical Support Document (TSD) for Describing Available Cancer Potency Factors provides
technical information support for the Air Toxics Hot Spots Program Risk Assessment Guidelines. The
TSD consists of 12 sections:
1. The TSD introduction.
2. A lookup table containing unit risk and cancer potency values.
3. A description of the methodologies used to derive the unit risk and cancer potency values
listed in the lookup table.
4. Chemical-specific summaries of the information used to derive unit risk and cancer potency
values.
5. A description of the use of toxicity equivalency factors for determining unit risk and
cancer potency factors for polychlorinated dibenzo-p-dioxins and dibenzofurans
(Appendix A).
6. A listing of Toxic Air Contaminant documents approved by the California Air Resources
Board (Appendix B).
7. Descriptions of the International Agency for Research on Cancer (IARC) and U.S.
Environmental Protection Agency (US EPA) carcinogen classifications (Appendix C).
8. An asbestos quantity conversion factor for calculating asbestos concentrations expressed as
100 fibers/m 3 from asbestos concentrations expressed as µg/m 3
(Appendix D).
9. US EPA IRIS inhalation unit risk and oral cancer potency factors available for chemicals
listed in the TSD (Appendix E).
10. A listing of Hot Spots cancer unit risk values which differ from corresponding US EPA IRIS
inhalation unit risk factors. (Appendix F).
11. Procedures for revisiting or delisting cancer potency factors by the program of origin
(Appendix G).
12. Exposure routes and study types used to derive cancer unit risks and slope factors
(Appendix H).
13. Additions and corrections from the prior document version (Appendix I).
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