Toxicological information
Acute toxicity:
- Rat oral LD50: liquid MBr in corn oil - 104 mg/kg microencapsulated MBr in corn oil - 133 mg/kg
- Rat inhalation LC50: 1175 mg/m³/8 hour
- Mouse inhalation LC50: 1540 mg/m³/2 hour
Effects of overexposure :
- Ocular Severe irritant: Contact with liquid or high concentrations of gas with the eyes may cause severe but usually reversible injury involving temporary blindness.
- Dermal Liquid splashed on clothing or leather or high gas concentrations held in contact with skin may cause skin burns with large blisters appearing after several hours. Less severe exposures may cause itching skin rash even after several days. May be absorbed through the skin in sufficient amount to cause systemic toxicity.
- Inhalation Acute poisoning from methyl bromide is characterized by marked irritation to the respiratory tract which may lead, in severe cases, to pulmonary edema. High concentrations may damage the liver, kidneys and central nervous system. Symptoms of poisoning include headache, dizziness, somnolence, vertigo, blurred vision, slurred speech, nausea and vomiting and possibly convulsions and coma. ONSET OF TOXIC SYMPTOMS MAY BE DELAYED FROM 30 MINUTES TO SEVERAL DAYS.
- Ingestion Severe irritant to mucous membranes and toxic poison if ingested, although ingestion is highly unlikely.
Chronic toxicity: Chronic exposure to low concentrations of methyl bromide may produce central nervous system effects. Signs include mental confusion, lethargy, inability to focus one's eye, incoordination and muscle weakness.
Repeated skin contact may cause dermatitis.
Mutagenicity: Mutagenic by the Ames Test MBr induced DNA damage in rat testis following inhalation exposure at 250 ppm (6 hours/day for 5 consecutive days). In vivo, MBr induced sister chromatid exchanges in bone marrow cells and micronuclei in peripheral erythrocytes of female mice exposed by inhalation for 14 days.
Carcinogenicity Studies conducted with MBr, exposing animals both by inhalation (rats & mice) and by oral route (fumigated feed, rats), showed that THERE WAS NO EVIDENCE OF CARCINOGENIC ACTIVITY. Not included in NTP 9th Report on Carcinogens. IARC Group 3 (animal inadequate evidence, human no data available).
Other: Single exposure vapour inhalation neurotoxicity study in rats:
---NOEL - 100 ppm
Acute oral toxicity (single dose) study in Beagle dogs:
---Lethal dose - 500 mg/kg
---No clinical signs were observed at 1 mg/kg
