and it seems they actually knew it. from wikipedia "Two months earlier, at Kriewald, then part of Germany, 19 people had died when 30 tonnes of ammonium nitrate

and it seems they actually knew it. from wikipedia "Two months earlier, at Kriewald, then part of Germany, 19 people had died when 30 tonnes of ammonium nitrate detonated under similar circumstances. It is not clear why this warning was not heeded"