Deep-sea divers use helium mix for safety and high-pitched voices

Summary: Deep-sea submarines use a gas mixture called heliox, which combines helium and oxygen, for long dives. This mixture improves safety and oxygen levels for crews on missions lasting up to 28 days.

Heliox has a humorous side effect: it makes voices sound high-pitched, similar to cartoon characters. This occurs because helium is less dense than oxygen, causing vocal cords to vibrate faster.

The use of heliox dates back to the 1930s, when it was first tested during a salvage operation after the USS Squalus sank. It helped divers avoid nitrogen narcosis and work more effectively underwater.

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