When doctors and Nobel Prize winners warned about a looming helium shortage and told us to stop wasting it on party balloons, people laughed. But it’s an irreplaceable element in many technological devices, some of them life-saving. And it’s running out fast.

News of a huge new helium gas field found in Tanzania has, for now, postponed a crisis that started 20 years ago. Yet, unless the Tanzania field is a harbinger of unimaginably large deposits elsewhere, it will only delay the inevitable: we’ll soon have no helium left.

No substitute

Helium is the second most abundant element in the universe. Sadly, most of it is in stars. On Earth, it’s formed from the radioactive decay of elements like uranium or thorium over millions of years. If not trapped, such as in rocks or underground caves, it is so light that it floats up through the atmosphere and slowly leaks into space. Also, unlike hydrogen, an even lighter gas, helium is inert: It almost never reacts with other chemicals. So it can’t get trapped in larger molecules—as hydrogen is trapped in water, for instance—that prevent its escape.

These properties, its lightness and its inertness, are also what make helium so valuable.

Because it’s inert, it helps in storing highly reactive and combustible rocket fuel. Welders use it as a gas shield, to keep out oxygen or other vapors that can damage the quality of the weld. It’s great for detecting leaks—in aerosols, air conditioners, fire extinguishers, nuclear reactors, you name it—because its small atoms can flow through the tiniest of cracks. Deep-sea divers breathe a mix of helium and oxygen, rather than the nitrogen-oxygen mix of normal air, which can be toxic and narcotic under high pressure.

Its biggest use is as a coolant. With a boiling point just a couple of degrees above absolute zero, liquid helium is the only thing that can keep large superconducting magnets cold enough to function. An estimated one fifth of the US’s annual helium consumption goes on magnetic resonance imaging (MRI) scanners, which contain such magnets. It’s also needed in low-temperature science experiments, such as those at the Large Hadron Collider.

AP Photo/John Minchillo Uncle Sam has gas.

Stock up

Helium is found sometimes in oil wells and sometimes trapped in rocks underground. Back in 1925, when its main use was in airships, the US Congress set up the National Helium Reserve (NHR), a deep underground reservoir and pipeline network spread across Texas, Oklahoma, and Kansas. The government encouraged private companies to mine helium and sell it to the NHR, creating the biggest stockpile in the world.

After the world wars, the US became the dominant supplier of helium. But helium prices didn’t cover the huge cost of maintaining the reserve, and, by 1996, the NHR was over a billion dollars in debt. So Congress voted to gradually shut it down and sell off the reserves. The 1996 Helium Privatization Act stipulated that all reserves be sold by 2015 to pay off the government’s original investment.

The upshot: Some 40% of the world’s reserve went on sale at bargain prices.

Balloon ban

By 2010, the fear that we’d run out of helium was being taken seriously (pdf). Caps were placed on helium use. Prices rose. The military and industry could afford it, but not scientists, or sometimes even hospitals; stories emerged of MRI machines having to be periodically shut down.

To ease the crisis, in 2013 Congress extended the NHR’s operation to 2021, and switched sales to a yearly auction until the NHR is two-thirds empty—leaving the final third for federal use.

Today, the NHR still has 24 billion cubic feet (670 million cubic meters) of helium, and the US has 153 billion cubic feet total in reserves. There are known reserves in Algeria, Australia, Poland, Russia, and Qatar—some 25% of the world’s reserves are located in the Persian Gulf. But it is still reliant on the natural gas industry and its refineries (pdf, p. 35), and 15 years of low prices has had a chilling effect on helium mining development, discouraging active exploration and development of further reservoirs. In 2013, there were just 12 helium plants worldwide.

Reuters/Navesh Chitrakar Don’t let it go.

African gold

At current rates of consumption, the world’s current known reserves will run out sometime between 2030 and 2040. This is why the Tanzania discovery is such a big deal. At an estimated 54 billion cubic feet, it is bigger than the NHR was at its peak.

The real breakthrough is in the way it was discovered. Nobody has ever found helium by looking for it deliberately, but only as a side-product of natural-gas exploration. The Tanzanian site, however, was found through modern prospecting. The theory is that rocks in which helium has formed (by radioactive decay) are slowly heated by the Earth’s core, letting the gas leak out, and it then gets caught in underground caves. The prospectors used their knowledge of the Rift Valley’s geology to find potential helium mines.

It’s a strategy that could be used elsewhere. Tanzania’s Rukwa Basin, where the discovery was made, is one of three areas that a Norwegian mining company, Helium One, is currently looking at, according to Diveena Danabalan of the University of Durham, who led the research. Further discoveries are likely in similar locations to the East African Rift, she says.

That said, the potential of the Tanzania find is still just that—potential. The 54 billion cubic feet is a current best estimate of what might be recoverable. Still untapped, it can’t yet be considered a reserve, Josh Bluett, technical director at Helium One, said.

Even if we get all that out of the Tanzanian mine, it would only extend global supplies seven more years. Worldwide consumption stands at eight billion cubic feet a year. Exploration of new mining sites will extend our stocks, but ultimately, helium is not a sustainable resource. ”We are using it faster than it is being found,” said Danabalan.

Running out

Even with new sites, helium will eventually run out. How soon depends on how many more sites like Tanzania we find and how rich they turn out to be.

It also depends, though, on how much we can reduce our need for it. Price rises have encouraged helium’s recycling—we never used to recycle copper or aluminum but do now. New materials, for instance, could allow MRI magnets to operate at higher temperatures and thus not require helium. If nothing else, helium will get so expensive that people will have no choice but to find alternatives.