The eruption of Mount Saint Helens in the Cascade Mountain Range of Washington State on 18 May 1980 resulted in a life-threatening and economically disruptive natural disaster that required the mobilization of supportive agencies from the State and Federal government for control. Because of the potential for further eruptions, the mechanism of death for those persons exposed to the initial blast was examined to aid in contingency planning.

Fatalities as a result of the eruption could be attributed to lack of understanding of the danger in the area of the mountain. Although several scientists were killed during the eruption, most were sight-seers who ignored the warning seismic activity and the precautionary blockade of the area. A few were outside of the well-publicized danger zone, but were caught in the rapidly moving mudslides or the ash cloud.