early 15c., from Latin contaminationem (nominative contaminatio), noun of action from past participle stem of contaminare (see contaminate). Figurative sense is from c.1620; specifically of radioactivity from 1913.
contamination con·tam·i·na·tion (kən-tām'ə-nā'shən)
The act or process of rendering something harmful or unsuitable.
The presence of extraneous, especially infectious, material that renders a substance or preparation impure or harmful.