TNT equivalent
Two explosions, half a second apart, occurred at 7:32 am on September 21, 1921, at Silo 110 of the plant, forming a crater wide and deep. In these explosions 10% of the 4,500 tonnes of fertilizer stored in the silo detonated. The explosions were heard as two loud bangs in north-eastern France and in Munich, more than 300 km away, and are estimated to have contained an energy of 1–2 kilotonnes TNT equivalent.