[Federal Register Volume 61, Number 242 (Monday, December 16, 1996)]
[Notices]
[Pages 66056-66057]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31780]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Toxicology Program; Availability of Technical Report on 
Toxicology and Carcinogenesis Studies of Nickel Sulfate Hexahydrate

    The HHS' National Toxicology Program announces the availability of 
the NTP Technical Report on the toxicology and carcinogenesis studies 
of nickel sulfate hexahydrate which is used in nickel plating, as a 
mordant in dyeing and printing textiles, as a blackening agent for zinc 
and brass, and in the manufacture of organic nickel salts. This 
chemical was studied because of potential for exposure in nickel 
industries.
    Toxicology and carcinogenicity studies were conducted by inhalation 
administration of nickel sulfate hexahydrate to groups of 63 to 65 
female F344/N rates at concentrations of 0, 0.12, 0.25, or 0.5 mg/m\3\ 
(equivalent to 0, 0.03, 0.06, or 0.11 mg nickel/m\3\) and groups of 80 
B6C3F1 mice of each sex at concentrations of 0, 0.25, 0.5, or 1 
mg/m\3\ (equivalent to 0, 0.06, 0.11, or 0.22 mg nickel/m\3\) for 6 
hours per day 5 days per week, for up to 104 weeks.
    Under the conditions of these 2-year inhalation studies, there was 
no evidence of carcinogenic \1\ activity of nickel sulfate hexahydrate 
in male or female F344/N rats exposed to 0.12, 0.25, or 0.5 mg/m\3\ 
(0.03, 0.06, or 0.11 mg nickel/m\3\). There was no evidence of 
carcinogenic activity of nickel sulfate hexahydrate in male or female 
B6C3F1 mice exposed to 0.25, 0.5, or 1 mg/m\3\ (0.06, 0.11, or 
0.22 mg nickel/m\3\).
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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 
studies that cannot be evaluated because of major flaws 
(``inadequate study'').
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    Exposure of rats to nickel sulfate hexahydrate by inhalation for 2 
years resulted in increased incidences of chronic active inflammation, 
macrophage hyperplasia, alveolar proteinosis, and fibrosis of the lung; 
lymphoid hyperplasia of the bronchial lymph node; and atrophy of the 
olfactory epithelium. Exposure of mice to nickel sulfate hexahydrate by 
inhalation for 2 years resulted in increased incidences of chronic 
active inflammation, bronchialization (alveolar

[[Page 66057]]

epithelial hyperplasia), macrophage hyperplasia, interstitial 
infiltration, and alveolar proteinois of the lung; lymphoid and 
macrophage hyperplasia of the bronchial lymph node; and atrophy of the 
olfactory epithelium.
    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 Nickel Sulfate 
Hexahydrate (CAS No. 10101-97-0) (TR-454) are available without charge 
from Central Data Management, NIEHS, MD E1-02, P.O. Box 12233, Research 
Triangle Park, NC 27709; telephone (919) 541-3419.

    Dated: November 13, 1996.
Samuel H. Wilson,
Deputy Director, NIEHS.
[FR Doc. 96-31780 Filed 12-13-96; 8:45 am]
BILLING CODE 4140-01-M