Toxicity Profiles

RAGs A Format for Benzo[b]fluoranthene - CAS Number 205992

Benzo[b]fluoranthene is a polycyclic aromatic hydrocarbon (PAH) with one five-membered carbon ring and four six-membered carbon rings. It is a crystalline solid with. Benzo[b]fluoranthene is virtually insoluble in water and is slightly soluble in benzene and acetone. There is no commercial production or known use of this compound. Benzo[b]fluoranthene is found in fossil fuels and occurs ubiquitously in products of incomplete combustion. It has been detected in mainstream cigarette smoke; urban air; gasoline engine exhaust; emissions from burning coal and from oil-fired heating; broiled and smoked food; oils and margarine; and in soils, groundwater, and surface waters at hazardous waste sites.

No absorption data were available for benzo[b]fluoranthene; however, by analogy to structurally-related PAHs, primarily benzo[a]pyrene, it would be expected to be absorbed from the gastrointestinal tract, lungs, and skin. No data were found concerning the acute, subchronic, chronic, developmental, or reproductive toxicity of benzo[b]fluoranthene in humans.

No long-term oral or inhalation bioassays were available to assess the carcinogenicity of benzo[b]fluoranthene in humans. Benzo[b]fluoranthene was tested for carcinogenicity in animals in dermal application, lung implantation, subcutaneous (s.c.) injection, and intraperitoneal (i.p.) injection studies. Dermal applications of 0.01-0.5% solutions of benzo[b]fluoranthene for life produced a high incidence of skin papillomas and carcinomas in mice. Sarcomas and carcinomas of the lungs and thorax were seen in rats receiving single lung implants of 0.1-1 mg benzo[b]fluoranthene. Newborn mice receiving 0.5 umol benzo[b]fluoranthene via i.p. injection developed liver and lung tumors and mice administered three s.c. injections of 0.6 mg benzo[b]fluoranthene developed injection site sarcomas.

Based on no human data and sufficient evidence for carcinogenicity in animals, EPA has assigned a weight-of-evidence classification of B2, probable human carcinogen, to benzo[b]fluoranthene.

The following is a presentation of the toxicity information associated with Benzo[b]fluoranthene:

• The Oral Slope Factor is 7.30E-01 (mg/kg-day)^-1.

• The Inhalation Unit Risk is 8.8E-02 (mg/m³)^-1.

• The Dermal Slope Factor is 2.35E+00 (mg/kg-day)^-1.
• The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.3100.