The US has been selling off its helium reserve, established in the 1920s to provide gas for airships – but even so, shortages have been occurring.

Some scientists believe a finite resource that could one day run out should not be used for party balloons.

In the universe as a whole, it is one of the commonest elements, second only to hydrogen in its abundance. On Earth it is relatively rare, and the only element that escapes gravity and leaks away into space.

“All of the other elements we’ve scattered around the globe, maybe we can go digging in garbage dumps to get them back,” says chemist Andrea Sella, of University College London (UCL).

“But helium is unique. When it’s gone it is lost to us forever.”

Helium has the lowest boiling point of any element, at -269C, just a few degrees above absolute zero (-273C).

“We’re going to be looking back and thinking, I can’t believe people just used to fill up their balloons with it, when it’s so precious and unique,” says Cambridge University chemist Peter Wothers, who has called for the end to helium-filled party balloons.

“It is something we need to think about.”

That would mean an end to the old party favourite of breathing in helium from a balloon, and then talking in a high-pitched voices – a result of helium’s fast-moving molecules. But maybe this would be no bad thing, as it can cause dizziness, headaches and even death.

The gas, which is formed by the decay of radioactive rocks in the earth’s crust, accumulates in natural gas deposits and is collected as a by-product of the gas industry.

The United States is currently the world’s biggest supplier, with the bulk of it stored near Amarillo, Texas, in the national helium reserve – which alone accounts for 35% of the world’s current supply.

This was set up in 1925 as a strategic store for supplying gas to US airships, while after World War Two it provided coolant for missiles and rockets for the military and Nasa.

USS Shenandoah, the world’s first helium-filled rigid airship

But since the mid-1990s, with growing civilian demand for helium in the manufacture of semi-conductors and for MRI scanners, among other things, the US has been clawing back the cost of storing the gas by gradually selling it off on the open market.

Despite this, the price of helium has doubled over the past 10 years.

Scare stories about this or that resource running out are a commonplace of doomsayers – but this autumn, the world got a taste of what a helium shortage could mean.

US semiconductor manufacturers knew that under the terms of a 1996 law, the US helium reserve was legally obliged to turn off the tap last month.