The salts of caesium are also soluble in water, and this complicates the safe handling of caesium.

After entering the body, caesium gets more or less uniformly distributed throughout the body, with the highest concentrations in soft tissue. As of 2005, caesium-137 is the principal source of radiation in the zone of alienation around the Chernobyl nuclear power plant.

A 1972 experiment showed that when dogs are subjected to a whole body burden of 3800 μCi/kg (140 MBq/kg, or approximately 44 μg/kg) of caesium-137 (and 950 to 1400 rads), they die within 33 days, while animals with half of that burden all survived for a year. Together with caesium-134, iodine-131, and strontium-90, caesium-137 was among the isotopes distributed by the reactor explosion that constitute the greatest risk to health.

The mean contamination of caesium-137 in Germany following the Chernobyl disaster was 2000 to 4000 Bq/m In April 2011, elevated levels of caesium-137 were also being found in the environment after the Fukushima Daiichi nuclear disasters in Japan.

It is among the most problematic of the short-to-medium-lifetime fission products because it easily moves and spreads in nature due to the high water solubility of caesium's most common chemical compounds, which are salts. The remainder directly populates the ground state of barium-137, which is stable.

Ba-137m has a half-life of about 153 seconds, and is responsible for all of the emissions of gamma rays in samples of caesium-137.

One gram of caesium-137 has an activity of 3.215 terabecquerel (TBq).

Caesium-137 is not widely used for industrial radiography because it is quite chemically reactive, and hence difficult to handle.

August 31, 2015 Subject: Announcement of Changes to the Therapeutic Products Directorate's List of Recognized Standards for Medical Devices Health Canada is pleased to announce changes to the Therapeutic Products Directorate's (TPD) List of Recognized Standards for medical devices.

The changes consist of: is posted on the Health Canada website.