contamination –n. made unfit for use by undesirable elements

radioactive isotopes –n. any one of different forms in which the atoms of a chemical element can occur—that have been exposed to radiation

fallout – n. the radioactive particles that are produced by a nuclear explosion and fall through the atmosphere

task – n. a job for someone to do

toxic – adj. containing poisonous substances

arson -n. when a person sets a fire to cause damage