Radioactive fallout emits alpha, beta, and gamma radiation.

Alpha particles emitted from fallout on the ground are not considered a serious hazard, since the source is outside the body. However, alpha particles are harmful if the alpha-emitting source is taken into the body.

The beta radiation which is much less penetrating than gamma radiation, may cause skin burns if the fallout remains on the body surface for a prolonged period of time.

Exposure from the gamma radiation is considered the major hazard as a result of fallout.