home edit2 whole TSD November 2002 PDF format - OEHHA

p-DIMETHYLAMINOAZOBENZENE
CAS No: 60-11-7
I. PHYSICAL AND CHEMICAL PROPERTIES (From HSDB, 1994)
Molecular weight 225.28
Boiling point
not available
Melting point 114-117 °C
Vapor pressure
not available
Air concentration conversion 1 ppm = 9.214 mg/m 3
II.
HEALTH ASSESSMENT VALUES
Unit Risk Factor: 1.3 E-3 (µg/m 3 ) -1
Slope Factor: 4.6 E+0 (mg/kg-day) -1
[Female rat liver tumor data (Kirby and Peacock, 1947), contained in Gold et al. database
(1984), expedited Proposition 65 methodology (Cal/EPA, 1992), cross-route extrapolation.]
III.
CARCINOGENIC EFFECTS
Human Studies
No studies on the potential carcinogenic effects of p-dimethylaminoazobenzene (DAB) in humans are
known to exist.
Animal Studies
IARC (1974) reviewed a number of studies on the carcinogenic potential of DAB in animals. DAB was
initially reported by Kinosita (1937) to induce liver tumors in rats after dietary exposure; tumors were
produced after 50 or more days of treatment (smallest total dose, 176 mg DAB). Sherman, Wistar and
Evans rats were found to be equally susceptible to the induction of liver tumors after exposure to diets
containing 600 mg/kg DAB (Sugiura and Rhoads, 1941).
Kirby and Peacock (1947) exposed male and female Wistar-derived rats to a low-protein diet (12%
casein) containing 0 or 600 mg/kg diet DAB. Group sizes were 8 animals/sex/group except for treated
females, where the group consisted of 7 animals. Four male rats received treated diet for 28 weeks,
followed by control diet; the other animals received treated diet for 33 weeks. At the end of the
treatment period, all animals received control diet until sacrifice at 52 weeks. Both male and female rats
developed hepatomas; Gold et al. (1984) list a tumor incidence of 0/8 and 5/7 for control and treated
(average dose, 20.9 mg/kg-day) females, respectively.
Druckrey and Küpfmüller (1948; reviewed by IARC, 1975) exposed rats to 1, 3, 10, 20 or 30 mg
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