Carcinogenicity Assessment for Lifetime Exposure
- Weight-of-Evidence Characterization
B1 (Probable human carcinogen - based on limited evidence of carcinogenicity in humans)
- Weight-of-Evidence Narrative:
- The observation of a statistically significant increase in incidence of lung cancer in exposed workers and observation of tumors, generally astrocytomas in the brain, in studies in two rat strains exposed by various routes (drinking water, gavage, and inhalation) forms the basis for this classification.
- This may be a synopsis of the full weight-of-evidence narrative. See IRIS Summary.
Quantitative Estimate of Carcinogenic Risk from Oral Exposure
- Dose-Response Data (Carcinogenicity, Oral Exposure)
- Tumor Type: Brain and spinal cord astrocytomas, Zymbal gland carcinomas and stomach papillomas/ carcinomas
- Test Species: Rats (Spartan Sprague-Dawley, males; Fischer 344, males; Sprague-Dawley, males)
- Route: Oral, Drinking water
- Reference: Biodynamics, 1980a,b; Quast et al., 1980a
Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure
Inhalation Concentrations at Specified Risk Levels