[Federal Register Volume 59, Number 10 (Friday, January 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-911]


[[Page Unknown]]

[Federal Register: January 14, 1994]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES
 

National Toxicology Program; Availability of Technical Report on 
Toxicology and Carcinogenesis Studies of o-Nitroanisole

    The HHS' National Toxicology Program announces the availability of 
the NTP Technical Report on the toxicology and carcinogenesis studies 
of o-nitroanisole which is used as an intermediate for the preparation 
of o-anisidine and in the manufacture of azo dyes.
    Toxicology and carcinogenicity studies were conducted by feeding 
groups of 60 F344 rats of each sex diets containing 0, 222, 666, or 
2,000 ppm o-nitroanisole and groups of 60 B6C3F1 mice of each sex diets 
containing 0, 666, 2,000, or 6,000 ppm o-nitroanisole for 103 weeks. In 
a companion study, male and female rats were fed 0, 6,000, or 18,000 
ppm o-nitroanisole for 6 months and maintained on untreated feed for 
1\1/2\ years.
    Under the conditions of these feed studies there was clear evidence 
of carcinogenic activity\1\ of o-nitroanisole in male and female F344 
rats that received diets containing 6,000 to 18,000 ppm for 6 months 
based on overall increased incidences of benign and malignant neoplasms 
of the urinary bladder, transitional cell neoplasms of the kidney, and 
benign and malignant neoplasms of the large intestine. There was a 
chemical-related increased incidence of mononuclear cell leukemia in 
male and female rats receiving diets containing 222, 666, or 2,000 ppm 
o-nitroanisole for 2 years. Marginally increased incidences of uncommon 
renal tubule neoplasms in male rats and forestomach neoplasms in male 
and female rats were considered uncertain findings. There was clear 
evidence of carcinogenic activity of o-nitroanisole in male B6C3F1 mice 
based on increased incidences of benign and malignant hepatocellular 
neoplasms. There was some evidence of carcinogenic activity of o-
nitroanisole in female B6C3F1 mice based on increased incidences of 
hepatocellular adenomas.
    Increased severity of nephropathy in male rats, and increased 
incidences of focal hyperplasia of the renal tubule epithelium and 
forestomach ulcers in male rats, and of transitional cell hyperplasia 
of the urinary bladder, focal hyperplasia of the forestomach, and 
hyperplasia of transitional epithelium of the kidney pelvis in male and 
female rats were associated with exposure to o-nitroanisole.
    Questions or comments about the Technical Report should be directed 
to Central Data Management at P.O. Box 12233, Research Triangle Park, 
NC 27709 or telephone (919) 541-3419.
    Copies of Toxicology and Carcinogenesis Studies of o-Nitroanisole 
(CAS No. 91-23-6) in F344 Rats and B6C3F1 Mice (Feed Studies) (TR-416) 
are available without charge from Central Data Management, NIEHS, MD 
AO-01, P.O. Box 12233, Research Triangle Park, NC 27709; telephone 
(919) 541-3419.

    Dated: January 7, 1994.
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 94-911 Filed 1-13-94; 8:45 am]
BILLING CODE 4140-01-M