Basically everything on the periodic table except extremely radioactive. Stereotypically
known as the scary stuff that Fukushima and Chernobyl
released from their damaged nuclear reactors poisoning the surrounding countryside forever.
The Fission Product releases from the spent fuel
pool fire expelled many times the radioactive
materials that one reactor
could have released.
elements were ejected from the core during
subsequent explosions and the fission products will be a hazard for many centuries to come.
lava consists of various fission Products.