Lanthanum is used as anodic material in nickel-metal hydride batteries. As most of the hybrid cars use nickel-metal hydride batteries, massive quantities of lanthanum are required for their production. A typical hybrid automobile battery for a Toyota Prius requires 10 to 15 kg of lanthanum. It also has uses in certain lighting systems, fiber optical communications, and phosphate removers for use in swimming pools.
Lanthanum has no known biological role. The element is not absorbed orally, and when injected its elimination is very slow.
Lanthanum has a low to moderate level of toxicity. In animals, the injection of lanthanum solutions produces glycaemia, low blood pressure, as well as damage to the spleen and hepatic alterations.
Lanthanum appears in hair samples in smokers and patients with signs of stress.