Caesium Chloride - Toxicity

Toxicity

Caesium chloride has a low toxicity to human and animals. Its median lethal dose (LD₅₀) in mice is 2300 mg per kilogram of body weight for oral administration and 910 mg/kg for intravenous injection. The toxicity of CsCl is related to its ability to lower the concentration of potassium in the body and partly substitute it in biochemical processes. Caesium chloride powder can irritate the mucous membranes and cause asthma.

Because of its high solubility in water, caesium chloride is highly mobile and can even diffuse through concrete. This is a drawback for its radioactive form which urges a search for more stable radioisotope materials. Commercial sources of radioactive caesium chloride are well sealed in a double steel enclosure. However, in the Goiânia accident in Brazil, such a source containing about 93 gram of 137CsCl, was stolen from an abandoned hospital and forced open by two scavengers. The blue glow emitted in the dark by the radioactive caesium chloride attracted the thieves and their relatives who were unaware of the associated dangers and spread the powder. This resulted in one of the worst radiation spill accidents in which 4 people died within a month from the exposure, 20 showed signs of radiation sickness, 249 people were contaminated with radioactive caesium chloride, and about a thousand received a dose exceeding a yearly amount of background radiation. More than 110,000 people overwhelmed the local hospitals, and several city blocks had to be demolished in the cleanup operations. In the first days of the contamination, stomach disorders and nausea due to radiation sickness were experienced by several people, but only after several days one person associated the symptoms with the powder and brought a sample to the authorities.