home edit2 whole TSD November 2002 PDF format - OEHHA

Comparison of Hot Spots Cancer Unit Risk Values Which Differ From Corresponding US
EPA IRIS Cancer Unit Risk Values
Resolution of
Chemical
OEHHA OEHHA RA OEHHA OEHHA RA Are OEHHA
RA
performed
considering
US EPA RA
information
based on newer
study compared
to the
corresponding
US EPA RA
RA received
external peer
review
received
public
comment
and US EPA
unit risk
values
essentially
similar? A the differences
between the
OEHHA and
US EPA RAs
will require
additional
research C
Acetaldehyde yes no yes yes yes no
Acrylonitrile yes no yes yes no no
Arsenic (inorganic, yes yes yes yes yes no
inhalation)
Asbestos no B no yes yes no no
Benzene yes no yes yes no no
Benzidine yes no yes yes no no
Bis(2-chloroethyl) ether yes no yes yes no no
Bis(chloromethyl)ether yes no yes yes no no
1,3-Butadiene yes yes yes yes yes no
Cadmium (and compounds) yes no yes yes no no
Carbon tetrachloride yes no yes yes no no
Chloroform yes yes yes yes no no
Chromium (hexavalent) yes no yes yes no yes
3,3'-Dichlorobenzidine yes no yes yes no no
1,4-Dioxane yes no yes yes no no
Epichlorohydrin yes no yes yes no no
Ethylene dibromide yes no yes yes no no
Ethylene dichloride yes no yes yes yes no
Formaldehyde yes yes yes yes yes no
Hexachlorobenzene yes yes yes yes yes no
Hexachlorocyclohexanes yes no yes yes no no
(technical grade)
Methylene chloride yes no yes yes no yes
Nickel compounds yes yes yes yes yes no
N-Nitroso-n-dibutylamine yes no yes yes no no
N-Nitrosodiethylamine yes no yes yes no no
N-Nitrosodimethylamine yes no yes yes no no
N-Nitrosodiphenylamine yes no yes yes yes no
Pentachlorophenol yes no yes yes no yes
2,4,6-Trichlorophenol yes no yes yes no yes
Abbreviations
RA: risk assessment CDHS: California Department of Health Services
Footnotes
A: Chemicals having a Hot Spots/IRIS unit risk ratio of greater than 0.5 but less than 2.
B: Both the CDHS RA and the US EPA RA were published in the same year.
C: This indicates instances where differences in scientific judgment on how to address data gaps in the information
used in the risk assessment for that chemical exist between Cal/EPA and US EPA; additional studies could
potentially eliminate those differences.
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