to this:
Nitromethane was not classified as an explosive substance until the explosion of a railway tank on July 1, 1958.
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For a long time, the largest explosion in the history of mankind was considered the explosion of a double salt warehouse - sulphate and ammonium nitrate in Oppau (Germany). The fertilizer was crushed into small explosions, which apparently caused detonation in the entire mass of the substance previously considered safe. The explosion turned out to be so powerful that along with the strong destruction in Oppau's own houses were also destroyed in Manheim, which is 6 km away. The explosive wave broke out glass at a distance of up to 70 km.

"Chemistry and Life" No. 5 1990