Which of the following is not an example of a natural disaster?

A nuclear accident is a human-made technological disaster caused by reactor or radiation failure, not a natural event.

A tsunami is a natural disaster driven by undersea earthquakes or landslides.

Heat waves are natural extremes of prolonged high atmospheric temperature.

An epidemic is a natural biological disaster from the rapid spread of disease.

Natural disasters arise from physical earth or weather processes without direct human engineering.

Radiation leaks such as Chernobyl and Fukushima are classed as anthropogenic hazards.