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Table 2 (continued):
Organ (Site) Tumor Type Route of
Exposure
Maltoni et al. (1983) benzene rat bioassay summary.
Sex
Dose
(mg/kgday)
Cochran-
Armitage Linear
Trend Test
Zymbal gland carcinomas inhalation 4 M, F 16.4 N/A
(single dose level)
Fisher Exact
Test
Difference in Cancer
Attack Rate per 100
(Dose-Control)
p = 0.002 5.1
Liver hepatomas inhalation 5 F 1.42 N/A
(single dose level)
p = 0.022 5.1
Source: CDHS (1984) TAC document. Results of Maltoni et al. (1983) studies.
1 Experiment 1: (#BT901), animals dosed for 52 weeks.
2 Experiment 2: (#BT902), 92-week interim results, dosing to be carried out for 104 weeks, 118-week
interim results.
3 Experiment 3: (#BT4004), inhalation exposure of 13-week old breeder rats for 104 weeks, 118-
week interim results.
4 Experiment 4: (#BT4004), inhalation exposure of 12-day old embryos for 104 weeks. Dose in utero
not considered, 118-week interim results.
5 Experiment 5: (#BT4006), inhalation exposure of 12-day old embryos for 15-weeks. Dose in utero
not considered, 118 week interim results.
The National Toxicology Program (NTP, 1983) conducted a 2-year bioassay on the carcinogenic
effects of oral (gavage) exposure to benzene in F344 rats and B6C3F 1 mice. Female rats and mice
were administered benzene in corn oil at doses of 0, 25, 50, and 100 mg/kg, 5 days/week, for 103
weeks. Male rats and mice were administered benzene at doses of 0, 50, 100, and 200 mg/kg, 5
days/week for 103 weeks. In F344 rats, statistically significant dose-related increases in the incidences
of neoplasms were reported for the oral cavity (males and females), Zymbal gland (males and females),
uterus (females) and skin (males). In B6C3F 1 mice, statistically significant dose-related increases in the
incidences of tumors were reported for the Zymbal gland (males and females), ovary (females),
mammary gland (females), Harderian gland (males and females), lung (males and females), preputial
gland (males) and for lymphoma/leukemia combined (males and females). Selected study data are listed
in Table 3.
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