US EPA

2969881 

Journal Article 

First experimental demonstration of the carcinogenic effects of benzene; long-term bioassays on Sprague-Dawley rats by oral administration 

Maltoni, C; Scarnato, C 

1979 

1 

La Medicina del Lavoro
ISSN: 0025-7818
EISSN: 2532-1080 

70 

5 

352-357 

English 

554913 

MEDLINE:554913 

The long-term effects of benzene (71432) administered orally were investigated in rats. Sprague-Dawley-rats were administered 50 or 250mg/kg benzene dissolved in olive oil by stomach tube daily, 4 to 5 days/week for 52 weeks. Animals were then followed until spontaneous death when they were autopsied. Histological examinations were performed on a number of organs. No acute or subacute toxic effects were apparent. Zymbal gland carcinomas were seen in 6.7 percent of females receiving 50mg/kg and in 25 percent of females receiving 250mg/kg benzene, but not in controls or males. Skin carcinomas were apparent in 6.2 percent of females receiving 250mg/kg benzene. Mammary carcinomas were seen in 13.3 and 21.9 percent of females receiving 50 and 250mg/kg benzene, respectively, and in 10 percent of female controls. Leukemia was detected in 12.1 percent of males and 3.1 percent of females receiving 250mg/kg, 6.7 percent of females treated with 50mg/kg, and 3.3 percent of female controls. One angiosarcoma, one hepatoma, and two other malignancies were found in males treated with 250mg/kg benzene, while three other malignancies were seen in females in the high dose group. The authors conclude that benzene was carcinogenic in laboratory animals. Benzene produces solid tumors at doses which do not produce important toxic effects.