A workplace emergency is a situation that threatens workers, customers, or the public; disrupts or shuts down operations; or causes physical or environmental damage. Emergencies may be natural or man-made. Examples include hurricanes, tornadoes, earthquakes, floods, wildfires, winter weather, chemical spills or releases, disease outbreaks, releases of biological agents, explosions involving nuclear or radiological sources, and many other hazards.

To protect workers, employers should expect the unexpected and carefully develop an emergency action plan. Planning helps ensure that everyone knows what to do when an emergency occurs. Many types of emergencies can be anticipated, which helps employers and workers plan and prepare.