home edit2 whole TSD November 2002 PDF format - OEHHA

N-NITROSOMORPHOLINE
CAS No: 59-89-2
I. PHYSICAL AND CHEMICAL PROPERTIES (From HSDB, 1994)
Molecular weight 116.11
Boiling point
224-225 °C (@ 747 mm Hg)
Melting point 29 °C
Vapor pressure
not available
Air concentration conversion 1 ppm = 4.75 mg/m 3
II.
HEALTH ASSESSMENT VALUES
Unit Risk Factor: 1.9 E-3 (µg/m 3 ) -1
Slope Factor: 6.7 E+0 (mg/kg-day) -1
[ Female hamster respiratory tract tumor data (Ketkar et al., 1983), contained in Gold et al.
(1987) database, expedited Proposition 65 methodology (Cal/EPA, 1992), with cross-route
extrapolation.]
III.
CARCINOGENIC EFFECTS
Human Studies
No studies on the potential carcinogenic effects of N-nitrosomorpholine in humans are known to exist.
Animal Studies
IARC (1978) reviewed a study in which 58 male NMRI mice were exposed to N-nitrosomorpholine in
drinking water at a concentration of 100 mg/l for the life of the animals (Bannasch and Müller, 1964;
Müller, 1964). Increases in liver tumor incidence were noted; 16/58 animals developed hepatocellular
adenomas. Treated animals also developed “numerous” lung adenomas and one lung squamous cell
carcinoma was observed. Only 1/17 controls developed lung adenomas.
Male and female MRC rats (15 animals/sex) were exposed to N-nitrosomorpholine in drinking water
(100 mg/l; total dose 500 mg) for 50 weeks, then observed for the life of the animal (Garcia and
Lijinsky, 1972). Male and females displayed increased incidences of liver tumors (hepatocellular
carcinomas and hemangioendotheliomias; 13/15 and 13/14 in males and females, respectively) and
nasal cavity tumors (9/15 and 5/14 in males and females, respectively). The study did not report that a
control group was included.
Male and female Syrian golden hamsters (20/sex/group) were given weekly subcutaneous injections of
N-nitrosomorpholine, which were one-fifth, one-tenth or one-twentieth of the LD50 of
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