This week marks the centenary of the Helium Act, signed by Calvin Coolidge and designed to encourage “the conservation, production, and exploitation of helium gas”.

Despite being the second-most abundant element in the universe, helium is rare on Earth because it is lighter than other atmospheric gases such as oxygen and nitrogen – this means it tends to rise so far above the planet’s surface that it escapes the pull of gravity and is lost to the vacuum of space.

The helium we use today comes from the natural radioactive decay of elements such as uranium and thorium in the Earth’s crust. The helium this process creates travels up through the ground, becoming trapped in pockets of natural gas that humans can then exploit.

Between 1903 and 1925, oil prospectors discovered multiple gas deposits in Kansas and Texas that contained small amounts of helium – between 1% and 2% by volume. Recognizing the extreme scarcity of this element and its potential military applications, Congress passed the Helium Act.

One of the provisions of this legislation was a ban on the export of helium from the United States, which is the reason the Hindenburg was full of highly-flammable hydrogen gas.

Thankfully, we now use kerosene to power our aircraft and such accidents are a distant memory…