How 1970s deodorant is still doing harm

By Laurence Knight

Fluorine is an evil gas. And it is also used to manufacture a string of other artificial gases, some of which nearly left mankind exposed to burning ultraviolet light - and are even now warming the planet.

"Fluorine is the tyrannosaurus rex of the periodic table," says chemistry professor Andrea Sella. "It will react spontaneously with every other element except for helium, neon and argon."

If you ever happen to lay eyes on pure, elemental fluorine, it looks fairly innocuous - a pale yellow gas - but in truth it is so dangerous that Sella's department at University College London does not even keep it in stock.