Boston

Molasses, a sticky sugar byproduct, refines into industrial alcohol and even explosives feedstock. World War I demand piled it into downtown Boston tanks. The day right after the 1919 flood, Prohibition was ratified — some say the distillery rushed to draw off rum alcohol first.

On Jan 15, 1919, a steel tank burst in downtown Boston, spilling ~8.7 million liters (12,000 tons) of molasses. A sticky brown wave 8m high at over 50 km/h killed 21 people, injured ~150, and flattened buildings: the Great Boston Molasses Flood, a bizarre disaster.