[Federal Register Volume 59, Number 178 (Thursday, September 15, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22811]
[[Page Unknown]]
[Federal Register: September 15, 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-Benzyl-p-Chlorophenol
Ths HHS' National Toxicology Program announces the availability of
the NTP Technical Report on the toxicology and carcinogenesis studies
of 0-benzyl-p-chlorophenol, an aryl halide biocide with use in
hospitals and households as a broad-spectrum germicide in disinfectant
solutions and soap formulations for general cleaning and disinfecting.
Two year toxiocology and carcinogenicity studies were conducted by
administering o-benzly-p-chlorophenol to groups of 80 male and 80
female rats in corn oil by gavage 5 days a week for 103 weeks at doses
of 0, 30, 60, or 120 mg/kg body weight for male rats and 0, 60, 120, or
240 mg/kg body weight for female rats. Groups of 70 male and 70 female
mice were administered o-benzly-p-chlorophenol in corn oil by gavage at
doses of 0, 120, 240, or 480 mg/kg body weight 5 days a week for 103
weeks.
Under the conditions of these 2-year gavage studies, there was no
evidence of carcinogenic activity\1\ of o-benzly-p-chlorophenol in make
F344/N rats receiving 30, 60, or 120 mg/kg body weight. There was
equivocal evidence of carcinogenic activity of o-benzyl-p-chlorophenol
in female F344/N rats based on the occurrence of two rare renal
transitional cell carcinomas. There was some evidence of carcinogenic
activity of o-benzyl-p-chlorophenol in male B6C3F1 mice based on
increased incidences of renal tubule adenoma and renal tubule adenoma
or carcinoma (combined). There was no evidence of carcinogenic activity
of o-benzyl-p-chlorophenol in female B6C3F1, mice receiving 120,
240, or 480 mg/kg.
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\1\The NTP uses five categories of evidence of carcinogenic
activity observed in each animal study: Two categories for positive
results (``clear evidence'' and ``some evidence''), one category for
uncertain findings (``equivocal evidence''), one category for no
observable effect (``no evidence''), and one category for studies
that cannot be evaluated because of major flaws (``inadequate
study'').
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o-benzyl-p-chlorophenol was nephrotoxic for male and female F344/N
rats and B6C3F1 mice. The severity of nephropathy was increased in
male and female rats and the incidence and severity of nephropathy was
increased in male and female mice. The incidence and severity of
nephropathy increased with length of treatment. Other lesions
considered to be associated with the nephropathy and the secondary
hyperparathyroidism in male rats and in male and female mice included
fibrous osteodystrophy and soft tissue mineralization. Increased
incidences of squamous cell hyperplasia of the fore-stomach were
observed in mice.
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-Benzyl-p-
Chlorophenol (CAS No. 120-32-1) in F344/N Rats and B6C3F1 Mice
(Gavage Studies) (TR-424) are available without charge from Central
Data Management, NIEHS, MD A0-01, P.O. Box 12233, Research Triangle
Park, NC 27709; telephone (919) 541-3419.
Dated: September 8, 1994.
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 94-22811 Filed 9-14-94; 8:45 am]
BILLING CODE 4140-01-M
