Helium

Helium is a colourless, odourless, tasteless, and non-toxic noble gas with the chemical symbol He and atomic number 2. It is the second most abundant element in the universe after hydrogen and plays a vital role in both scientific and industrial contexts. Despite its cosmic abundance, helium is relatively scarce on Earth, as its low atomic mass allows it to escape the planet’s atmosphere over geological timescales. Helium is distinguished by its remarkable physical properties—such as extremely low boiling and melting points, chemical inertness, and high thermal conductivity—making it indispensable in numerous everyday, industrial, and economic applications.

Physical and Chemical Properties

Helium remains gaseous under all normal temperature and pressure conditions and only liquefies at −269°C, just a few degrees above absolute zero. It is completely non-reactive, being part of the noble gas family, and forms no stable chemical compounds under standard conditions. Its density is the lowest of any gas, about one-seventh that of air, and it possesses the highest thermal conductivity and specific heat among the gases.
The isotope helium-4 (⁴He) constitutes most naturally occurring helium, while helium-3 (³He) is rare and of particular interest in advanced scientific research, including cryogenics and nuclear fusion studies.

Discovery and Occurrence

Helium was first detected in 1868 by the French astronomer Pierre Janssen and the English scientist Norman Lockyer during a solar eclipse, when an unknown yellow spectral line was observed in the Sun’s light—later identified as helium. It was subsequently isolated on Earth in 1895 by the Scottish chemist Sir William Ramsay, who found it in the mineral cleveite.
Most terrestrial helium today is obtained as a by-product of natural gas extraction, where it accumulates over millions of years through the radioactive decay of uranium and thorium. Large reserves are found primarily in the United States, Qatar, Algeria, and Russia, making helium both a strategic and economically sensitive resource.

Everyday Applications

Though invisible and inert, helium is present in several aspects of daily life.

• Balloons and Airships: Helium’s low density and non-flammable nature make it a safe replacement for hydrogen in party balloons, weather balloons, and blimps.
• Breathing Mixtures: In deep-sea diving, helium-oxygen mixtures (heliox) are used to prevent nitrogen narcosis and decompression sickness. Helium’s low density reduces breathing resistance under high pressure.
• Consumer Electronics: It is employed in cooling systems within electronics and optical fibre manufacturing. The inert nature of helium prevents chemical contamination during delicate processes.
• Leak Detection: Due to its small atomic size and inertness, helium is used to detect microscopic leaks in high-vacuum systems, pipelines, and sealed electronic equipment, a crucial process in industries and laboratories.

Industrial and Technological Applications

Helium plays a vital role in numerous high-technology and industrial operations, many of which rely on its unique cryogenic and inert characteristics.

• Cryogenics: The largest single use of helium lies in cryogenic cooling, particularly in maintaining the superconducting magnets used in magnetic resonance imaging (MRI) scanners, particle accelerators, and nuclear magnetic resonance (NMR) spectroscopy equipment. Liquid helium, the coldest known liquid, is essential for reaching temperatures close to absolute zero.
• Welding and Manufacturing: Helium is used as a shielding gas in arc welding of materials such as aluminium, stainless steel, and titanium. It protects molten metal from oxidation, resulting in stronger welds and cleaner finishes.
• Semiconductor Industry: In electronics manufacturing, helium is used for cooling, pressurising, and purging processes. Its stability ensures that no unwanted chemical reactions occur, maintaining high product yields in the production of microchips and optical fibres.
• Aerospace and Rocketry: Helium is indispensable in space exploration, used to pressurise and purge fuel tanks in rockets. Because of its inertness and low temperature, it prevents combustion and contamination during propulsion system operations.
• Energy Sector: It is employed in gas chromatography, nuclear reactors, and superconducting energy storage systems, owing to its stability and cooling ability.

Economic Importance and Global Supply

Helium’s economic value has grown significantly due to its limited availability and wide-ranging industrial uses. It is considered a non-renewable resource on Earth, as once released into the atmosphere, it escapes into space. The global helium supply is concentrated in a few regions, notably the United States (especially the Hugoton and Panhandle gas fields), Qatar, Algeria, and Russia.
The price of helium has fluctuated in recent decades due to supply constraints, maintenance shutdowns, and growing demand from medical and technology sectors. Helium extraction is energy-intensive, as it must be separated from natural gas using cryogenic distillation. Consequently, economic factors such as energy costs and geopolitical stability play a significant role in determining helium availability and pricing.
Efforts to mitigate shortages have led to the development of helium recycling systems—particularly in hospitals and research institutions—to capture and re-liquefy helium gas for reuse. Governments and private companies are also investing in new exploration projects and strategic reserves, such as the U.S. Federal Helium Reserve, to safeguard future supply chains.

Environmental and Safety Aspects

Helium is entirely non-toxic and non-flammable, posing no direct health hazards. However, inhaling helium directly from pressurised containers can cause asphyxiation due to oxygen displacement and pressure-related injuries. The main environmental concern lies in its irreversible loss to the atmosphere after use, leading to long-term depletion of accessible reserves.
From a sustainability standpoint, the emphasis is on helium conservation and recovery, particularly in scientific facilities where large quantities are used for cooling. Unlike most gases, helium cannot be synthesised economically, making conservation critical for long-term availability.

Emerging and Future Applications

New technologies continue to broaden helium’s importance. Quantum computing relies on helium-cooled superconducting circuits, as stable cryogenic conditions are essential for quantum bit (qubit) functionality. In space research, helium serves as a coolant for telescopes and detectors, such as those aboard the James Webb Space Telescope. Additionally, the isotope helium-3 is gaining attention for potential use in nuclear fusion reactors, offering a cleaner and safer alternative energy source.
In medical innovation, helium is used in respiratory treatments, cryosurgery, and in the development of high-field MRI systems. The expanding global reliance on advanced imaging and data technologies ensures that helium will remain a key enabler of progress.
Helium’s combination of safety, inertness, and cryogenic capability places it at the heart of numerous modern industries, from healthcare and computing to aerospace and clean energy. As supplies become increasingly constrained, strategic management and technological innovation will determine how effectively this rare and essential element supports human advancement in the decades to come.