Toxicity Profiles

RAGs A Format for Dibenz[a,h]anthracene - CAS Number 53703

Dibenz[a,h]anthracene is a polycyclic aromatic hydrocarbon (PAH) with five aromatic carbon rings. Dibenz[a,h]anthracene exists as crystalline plates or leaflets and is insoluble in water; slightly soluble in alcohol and ether; and soluble in petroleum ether, benzene, toluene, xylene, oils, and other organic solvents. No commercial production or use of dibenz[a,h]anthracene is known. It occurs as a component of coal tars, shale oils, and soots and has been detected in gasoline engine exhaust, coke oven emissions, cigarette smoke, charcoal broiled meats, vegetation near heavily traveled roads, and surface water and soils near hazardous waste sites.

Dibenz[a,h]anthracene is poorly absorbed from the digestive tract. No human studies were available to evaluate the toxicity of dibenz[a,h]anthracene. In animals, depressed immune responses were observed in mice following single or multiple subcutaneous injections of dibenz[a,h]anthracene. Weekly subcutaneous injections of 0.05% dibenz[a,h]anthracene for 40 weeks produced lymphoid tissue changes, decreased spleen weights, and liver and kidney lesions in mice. Weekly intramuscular injections of 20 mg/kg promoted the development of arteriosclerotic plaques in chickens.

No epidemiologic studies or case reports addressing the carcinogenicity of dibenz[a,h]anthracene in humans were available. In animals, dibenz[a,h]anthracene has produced tumors by different routes of administration (oral and dermal), having both local and systemic carcinogenic effects. After administration, dibenz[a,h]anthracene produced pulmonary adenomatosis, alveologenic carcinomas of the lung, hemangio-endotheliomas of the pancreas and mesentery/abdominal lymph nodes, mammary carcinomas (females), forestomach papillomas, and skin papillomas. Based on no human data and sufficient evidence for carcinogenicity in animals, EPA has assigned dibenz[a,h]anthracene a weight-of-evidence classification of B2, probable human carcinogen.

The following is a presentation of the toxicity information associated with Dibenz[a,h]anthracene.

Carcinogenic Health Effects
  • The Oral Slope Factor is 7.30E+00 (mg/kg-day)-1.

  • The Inhalation Unit Risk is 8.8E-01 (mg/m3)-1.

  • The Dermal Slope Factor is 2.35E+01 (mg/kg-day)-1.
  • The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.3100.