Schweizerhalle (Sandoz fire)

The warehouse in the Schweizerhalle industrial area held 1,351 tonnes of chemicals: insecticides, herbicides and mercury compounds. The fire broke out in the early hours of 1 November 1986; about 10,000 m³ of water was used to put it out, with nowhere to be held back.

Into the river went dinitro-ortho-cresol, organophosphates such as disulfoton, thiometon, parathion and fenitrothion, and the herbicide metoxuron. Fish died in large numbers, eels above all; dead fish were collected as far as Cologne and pollution was measured down to the Netherlands. The cause of the fire was never established.

The accident sped up cooperation among the Rhine states, with the 1987 Rhine Action Programme, and in Switzerland led to the federal Ordinance on Major Accidents, in force from 1 April 1991.