Toxicity Profiles

RAGs A Format for Bromoform - CAS Number 75252

Bromoform, also referred to as tribromomethane, is a halogenated aliphatic hydrocarbon. Bromoform is a colorless, heavy liquid with an odor and taste similar to chloroform. It is sparingly soluble in water but is soluble in ethanol, ethyl ether, benzene, solvent naphtha, and fixed and volatile oils. It is produced commercially from chloroform. Bromoform is used as an intermediate in organic synthesis; in gauge fluids; as a solvent for waxes, greases, and oils; as an ingredient in fire-resistant chemicals; and as a heavy-dense liquid in separating mixtures of chemicals. In addition, it has been used formerly in pharmaceuticals as a sedative and antitussive. romoform is formed as a byproduct during water chlorination when chlorine reacts with endogenous organic materials and bromide ions.

In humans, accidental ingestion of bromoform has led to listlessness, headache, and vertigo and at higher doses to central nervous system depression, coma, and death. The estimated lethal dose for a 10- to 20-kg child is 250 to 500 mg/kg. Exposure to bromoform vapor has caused irritation of the respiratory tract, pharynx, and larynx, as well as lacrimation and salivation. In animals, the liver, kidneys, and central nervous system are the primary target organs for bromoform toxicity. The principal cause of death following acute oral exposure is central nervous system depression.

The epidemiological evidence for an association between ingestion of chlorinated drinking water containing bromoform and increased cancer risk is inadequate. One long-term oral study and a lung tumor assay provide evidence of carcinogenicity for bromoform in animals. An increased incidence of intestinal tumors was seen in female rats, and an increased incidence of lung tumors was seen in male mice administered intraperitoneal injections of bromoform. Based on EPA guidelines, bromoform was assigned to weight-of-evidence group B2, probable human carcinogen.

The following is a presentation of the toxicity information associated with Bromoform:

• The Oral Chronic Reference Dose is 2.00E-02 (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 NTP study from 1989.
• The Oral Chronic Reference Dose study target organ is liver.
• The Oral Chronic Reference Dose study critical effect is lesions.
• The overall confidence in the Oral Chronic Reference Dose is medium.
• The Dermal Chronic Reference Dose is 1.20E-02 (mg/kg-day).
• The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.6000.

• The Oral Slope Factor is 7.90E-03 (mg/kg-day)^-1.
• The Oral Slope Factor study target organ is large intestine.
• The Oral Slope Factor study cancer type is neoplastic lesions.
• The Oral Slope Factor is based on the NTP study from 1988.
• The Inhalation Unit Risk is 1.1E-03 (mg/m³)^-1.
• The Inhalation Unit Risk study target organ is See Oral.
• The Inhalation Unit Risk study cancer type is See Oral.
• The Inhalation Unit Risk is based on the See Oral study from See Oral.
• The Dermal Slope Factor is 1.32E-02 (mg/kg-day)^-1.
• The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.6000.