| Natural | Industrial | Terrorist | |
|---|---|---|---|
| Chemical | __ | Accidental release of methyl isocyanate in Bhopal, India, 1984 | Release of Sarin by Aum Shinrikyo, Tokyo subway, 1995 |
| Biologic | Spanish flu pandemic, 1918 | US anthrax attacks, 2001 | |
| Radiologic | Tsunami affecting Fukushima nuclear power plant, Okuma, Japan, 2011 | Three Mile Island, 1979 Chernobyl, 1986 | Dirty bomb, Chechen rebels 1995 |
| Nuclear | Solar flairs | __ | __ |
| Explosive | Mount St. Helens volcanic eruption, 1980 | Fire at petroleum plant in Abule-Egba, Lagos, Nigeria, 2006 | Suicide bombers |