Caesium, particularly isotopes Cs-135, Cs-137, and Cs-138, can be dispersed beyond local areas after nuclear accidents like Fukushima due to its low melting point and high evaporation temperature. It can be transported via steam and deposited on dust, as well as being decay products of noble gases like xenon, which are easily airborne. The chemical reactivity of caesium means it is more likely to exist as a salt in radioactive dust rather than as a metal. While the chemical form may change, the radioactivity of caesium remains unaffected by its chemical state, as radioactive decay is a property of the nucleus. The discussion highlights the complexities of nuclear decay and its minimal impact on chemical bonding, emphasizing that the half-life of isotopes is primarily determined by nuclear configuration rather than electron interactions.