fall·out 
(fôlout′)
(fôlout′)n.
1.
a. The slow descent of minute particles of debris in the atmosphere following an explosion, especially the descent of radioactive debris after a nuclear explosion.
b. The particles that descend in this fashion.
2. An incidental result or side effect: "Other social trends also have psychiatric fallout, and the people who suffer can't afford treatment" (Martha Farnsworth Riche).