the.com/contamination
The uninvited guest who arrives the instant you stop watching the door.
means The unwanted introduction of something harmful or impure into a substance, surface, or system where it doesn't belong.
from From Latin contaminare, to mingle or defile, rooted in tangere, to touch — pollution by unwanted contact.
Cross-contaminationHow one raw chicken ruins an entire kitchen.
Clean roomsEngineered to under one dust speck per imagination.
Half-lifeRadioactive contamination can outlast every civilization that made it.