PEPCON disaster happened in 1988.
Luzhniki disaster happened in 1982.
Knockshinnoch Disaster happened in 1950.
Seveso disaster happened in 1976.
Abbeystead disaster happened in 1984.
Ibrox disaster happened in 1971.
The chemical fire and explosions at the Pacific Engineering Production Company of Nevada occurred in http://www.answers.com/topic/henderson-nevada?initiator=WANS on May 4, 1988.
A disaster can happen at any time. The trigger depends on the kind of disaster.
Marchioness disaster happened in 1989.
Feyzin disaster happened in 1966.
Patria disaster happened in 1940.
Eyemouth disaster happened in 1881.
Disaster Report happened in 2002.
Ryongchon disaster happened in 2004.
Kaprun disaster happened in 2000.
Niamiha disaster happened in 1999.
Spyros disaster happened in 1978.
Valtellina disaster happened in 1987.