This metal played a part in the worst car crash in history, the 1955 Le Mans disaster, helping to make the resulting inferno explosively dangerous. Yet despite its fiery reputation, and its proneness to corrosion, magnesium has regained its historic role in making planes and cars lighter and more efficient. Presenter Laurence Knight visits Magnesium Elektron, the company behind the alloy used in the ill-fated Le Mans car, to find out how a new breed of alloys has exorcised the demon's in this metal's past. We also hear from researcher Kristin Persson about an entirely new role magnesium could play in the car industry - as an even lighter and more compact replacement for lithium-ion batteries in electric vehicles.