I think it is unlikely it is the "largest ecological disaster in US history". We could compare it to the Dust Bowl http://en.wikipedia.org/wiki/Dust_Bowl , or the logging of old growth forest http://en.wikipedia.org/wiki/Old_growth_forest#Logging or the draining of the Everglades http://en.wikipedia.org/wiki/Draining_and_development_of_the... and it might not be as large. Consider also the introduction of invasive species such as Chestnut blight http://en.wikipedia.org/wiki/Chestnut_blight or red fire ants http://en.wikipedia.org/wiki/Red_imported_fire_ant#Ecologica... to put it into perspective. It seems too convenient, a collective self-deception, to point at a non-US company and say they have caused the worst ecological destruction in the US.