Hydrogen

Yes this is the gas that allowed the Hindenburg to float through the air and ended up bursting into flames. But, used properly it is a perfectly safe gas.

Hydrogen is the lightest of all gases and Hydrogen comprises 98% of the known universe. Colorless, odorless, tasteless and nontoxic, hydrogen exists as a gas at atmospheric temperatures and pressures. When cooled to its boiling point of -423°F (-253°C), hydrogen becomes a liquid and all other gases, except helium become solids at this temperature.

Hydrogen is flammable and burns in air with a pale blue, almost invisible flame. In its gaseous form, hydrogen dissipates quickly. These unique properties call for strict safety measures in hydrogen use and storage.

Hydrogen has many uses from arc welding shielding gases to fuel cells to rocket propellant. Other uses include petroleum refining processes, chemical processing of plastics, hydrogenation of food grade oils, protective atmospheres for metal production and plasma welding and cutting operations.