Toxicity Profiles

RAGs A Format for Heptachlor Epoxide - CAS Number 1024573

Heptachlor epoxide is a manufactured chemical that does not occur naturally. Pure heptachlor epoxide is a crystalline white powder that is a break down product of heptachlor and chlordane. The epoxide is more likely to be found in the environment than heptachlor because Heptachlor epoxide degrades slower and, as a result, is more persistent than heptachlor. Heptachlor epoxide is not produced commercially in the United States.

Heptachlor and heptachlor epoxide are clearly toxic to humans and animals and can damage the nervous system. No studies were available regarding the specific toxic effects in humans after exposure to heptachlor epoxide alone. In laboratory animals, the liver and central nervous system are the primary target organs for heptachlor epoxide toxicity. Oral doses in animals produced hypoactivity, ruffled fur, increased mortality, muscle spasms, and convulsive seizures.

No epidemiological studies or case reports addressing the carcinogenicity of heptachlor epoxide in humans were available. Studies with laboratory animals demonstrated that heptachlor epoxide causes liver cancer in mice and rats. Based on EPA guidelines, heptachlor epoxide was assigned to weight-of-evidence group B2, probable human carcinogen.

The following is a presentation of the toxicity information associated with Heptachlor epoxide.

Noncarcinogenic Health Effects
  • The Oral Chronic Reference Dose is 1.30E-05 (mg/kg-day).
  • The Oral Chronic Reference Dose has a modifying factor of 1.
  • The Oral Chronic Reference Dose has an uncertainty factor of 1000.
  • The Oral Chronic Reference Dose is based on the Dow Chemical Co. study from 1958.
  • The Oral Chronic Reference Dose study target organ is liver.
  • The Oral Chronic Reference Dose study critical effect is increased weight to body ratio.
  • The overall confidence in the Oral Chronic Reference Dose is low.

  • The Dermal Chronic Reference Dose is 9.36E-06 (mg/kg-day).
  • The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.7200.

Carcinogenic Health Effects
  • The Oral Slope Factor is 9.10E+00 (mg/kg-day)-1.
  • The Oral Slope Factor study target organ is liver.
  • The Oral Slope Factor study cancer type is carcinoma.
  • The Oral Slope Factor is based on the Velsicol study from 1973.

  • The Inhalation Unit Risk is 2.6E+00 (mg/m3)-1.
  • The Inhalation Unit Risk study target organ is liver.
  • The Inhalation Unit Risk study cancer type is carcinoma.
  • The Inhalation Unit Risk is based on the Velsicol study from 1973.

  • The Dermal Slope Factor is 1.26E+01 (mg/kg-day)-1.
  • The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.7200.