[Federal Register Volume 61, Number 85 (Wednesday, May 1, 1996)]
[Notices]
[Pages 19305-19306]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-10833]




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DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Toxicology Program; Availability of Technical Report on 
Toxicology and Carcinogenesis Studies of Diethylphthalate with Dermal 
Initiation/Promotion Study of Diethylphthalate and Dimethylphthalate

    The HHS' National Toxicology Program announces the availability of 
the NTP Technical Report on the toxicology and carcinogenesis studies 
of Diethylphthalate. Diethylphthalate and Dimethylphthalate are used as 
phthalte plasticizers in an extensive array of products.

    Toxicology and carcinogenicity studies were conducted by dermal 
administration of diethylphthalate to groups of 60 F344/N rats of each 
sex at doses of 0, 100, or 300 L and to groups of 60 
B6C3F1 mice of each sex at doses of 0, 7.5, 15, or 30 
L. Neat chemical was applied to rats for 5 days per week for 
103 weeks and up to 10 animals per group were evaluated after 15 
months. Mice received doses in 100 L of acetone for 5 days per 
week for 103 weeks with a 1 week recovery period, and up to 10 animals 
per group were evaluated after 15 months.

    An additional group of 50 male Swiss (CD-1) mice were 
dosed dermally with diethylphthalate of dimethylphthalate to study 
their effect as initiators and promoters. They were tested as 
initiators with and without 12-Otetradecanoylphorbol and they were 
tested as promoters with and without the known skin tumor initiator 
7,12-dimethylbenzanthrancene.

    Under the conditions of these 2-year dermal studies, there was no 
evidence of carcinogenic activity \1\ of

[[Page 19306]]

diethylphthalate in male or female F344/N rats receiving 100 or 300 
L. There was equivocal evidence of carcinogenic activity of 
diethylphthalate in male and female B6C3F1 mice based on 
increased incidences of hepatocellular neoplasms, primarily adenomas.
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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 
and cannot be evaluated because of major flaws (``inadequate 
study'').
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    In the initiation/promotion model, there was no evidence of 
initiating or promoting activity of diethylphthalate or 
dimethylphthalate in male Swiss (CD-1) 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 
Diethylphthalate/Dimethylphthalate (CAS Nos. 84-66-2 and 131-11-3) (TR-
429) 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: March 27, 1996
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 96-10833 Filed 4-30-96; 8:45 am]
BILLING CODE 4140-01-M