A radioactive element found in fallout from atomic or nuclear explosions.
An isotope of strontium which is formed in nuclear reactions and, because it is part of the fallout of nuclear explosions, can enter the food chain, attacking in particular the bones of humans and animals.
A radioactive isotope that emits beta rays: it is a radiation hazard.
A radioactive isotope characterized by a half-life of approximately 25 years, alternatively referred to as radiostrontium.