Lithium, Elemental

... Atmospheric oxidation of molten lithium led to an explosion. A high degree of correlation of incidence of explosions with high atmospheric humidity was demonstrated, with the intensity of explosion apparently directly related to the purity of the sample of metal.

... The powdered metal reacts explosively with water ... Prolonged contact with steam forms a thermally insulating layer which promotes overheating of the metal and may lead to a subsequent explosion as the insulating layer breaks up.