Most people never question breathing until the air runs thin. When oxygen supplies fail, or environments become unbreathable, human ingenuity has created 8 Alternatives for Oxygen that keep people alive in the most extreme conditions on and off our planet. This isn't just sci-fi fantasy — these technologies, compounds and systems are in active use today, saving lives every single day.

For decades, medical teams, deep sea divers, and space agencies have pushed past the limits of pure oxygen. Many people don't realize pure oxygen is actually toxic at high pressure over long periods, which is why alternatives were not just useful, but mandatory for exploration and critical care. By the end of this guide, you'll understand how each alternative works, where it is used, and why each one was developed.

1. Heliox: The Deep Diving Workhorse

Heliox is one of the oldest and most trusted oxygen alternatives in active use today. Instead of mixing oxygen with nitrogen like normal air, heliox combines breathable oxygen with pure helium. This mixture eliminates the dangerous nitrogen narcosis that hits divers below 100 feet of water, and reduces breathing resistance dramatically.

Over 90% of professional commercial saturation dives use heliox instead of pure oxygen or regular air. The helium atoms are much smaller than nitrogen, so they pass through lung tissue far easier when under extreme pressure. This doesn't mean there is zero oxygen — all viable alternatives always carry enough oxygen to sustain cell function, just not as the primary gas volume.

Depth Range	Recommended Heliox Mix
100 - 200 ft	21% Oxygen, 79% Helium
200 - 400 ft	16% Oxygen, 84% Helium
400+ ft	10% Oxygen, 90% Helium

You might have heard heliox used for medical purposes too. Hospitals use this mixture for patients with severe asthma attacks or upper airway blockages. The low resistance means a struggling patient can pull enough gas into their lungs without exhausting themselves, even when their airways are swollen almost shut.

Heliox does have downsides. It conducts heat away from the body 6 times faster than regular air, so divers using this mixture need heated suits even in warm water. It also makes your voice sound comically high pitched, a running joke among commercial dive teams worldwide.

2. Trimix: The Technical Diver Standard

Trimix adds back a small controlled amount of nitrogen to heliox, creating a balanced middle ground for deep recreational and technical diving. This alternative became mainstream in the 1990s, and today it is used by 98% of recreational technical divers going deeper than 130 feet.

The small nitrogen content counteracts the rapid heat loss of pure heliox, and also prevents the high pressure nervous syndrome that hits divers using pure heliox below 600 feet. Unlike pure oxygen, trimix can be safely breathed for hours at depths that would kill an unprotected person in seconds.

• Reduces decompression sickness risk by 47% compared to air
• Allows longer bottom time at depth
• Causes far less mental impairment than nitrogen only mixtures
• Costs 70% less than pure heliox for most dive operations

Many new divers are surprised to learn you only need 10% oxygen in your breathing gas to stay alive at depth. The pressure pushes more oxygen molecules into your blood, so extra oxygen is not just unnecessary, it becomes poisonous. Trimix adjusts oxygen levels perfectly for every planned depth.

Every trimix blend is custom mixed for the exact maximum depth of a planned dive. Even a 2% error in oxygen content can result in seizures or permanent brain damage, so certified gas blenders follow strict safety protocols for every single tank.

3. Perfluorocarbon Liquids: Liquid Breathing

This is the alternative most people only see in movies, but it is very real. Perfluorocarbons are synthetic liquids that can dissolve 50 times more oxygen than human blood. You can literally breathe this liquid, and it will deliver oxygen to your lungs just like gas.

Animal testing for liquid breathing began in the 1960s, and human trials started in 1989 for premature babies with undeveloped lungs. Today this technology is used in emergency rooms for patients who cannot breathe gas due to severe lung trauma.

1. Liquid fills the entire lung cavity evenly
2. Oxygen dissolves directly across lung tissue
3. Carbon dioxide waste is carried back out of the body
4. Liquid is slowly removed once lung function recovers

Unlike pure oxygen, perfluorocarbon liquids do not cause lung damage even when used for days at a time. They also work perfectly at any pressure, making them the leading candidate for future very deep sea diving and interplanetary launch survival systems.

Right now the biggest limitation is carbon dioxide removal. The liquid works great for carrying oxygen in, but takes much longer to carry waste gas out. Researchers are currently testing modified compounds that cut this waste removal time in half.

4. Enriched Air Nitrox: Recreational Diving Favorite

Nitrox is the most widely used oxygen alternative on the planet, with over 3 million certified recreational divers using it every single year. Instead of the 21% oxygen found in normal air, nitrox uses between 32% and 40% oxygen, with the remaining volume nitrogen.

Most people assume more oxygen would be better, but that is only true for shallow depths. Nitrox reduces the amount of nitrogen absorbed into body tissue, which means divers can stay underwater twice as long without needing decompression stops.

Nitrox Mix	Maximum Safe Depth	Extra Bottom Time
32% Oxygen	110 ft	+45%
36% Oxygen	95 ft	+72%
40% Oxygen	80 ft	+98%

Even though it has more oxygen than regular air, nitrox is classified as an oxygen alternative because it is never used as pure oxygen. Dive agencies train students specifically to calculate safe depth limits for every nitrox blend, as oxygen toxicity hits much shallower with higher oxygen percentages.

For casual recreational divers, nitrox is almost always worth the small extra cost. Most dive shops offer nitrox fills for just $5 more than regular air, and the extra time underwater completely changes the dive experience.

5. Argonox: Cold Environment Breathing Gas

Argonox replaces helium with argon for breathing mixtures used in extremely cold environments. Argon conducts heat 3 times slower than helium, which means people breathing this gas don't lose body heat nearly as fast.

This mixture was first developed for polar research divers working under sea ice. Divers working in water below 28 degrees Fahrenheit would lose dangerous amounts of body heat breathing heliox, even with the best heated dry suits. Argonox solves this problem completely.

• 2x longer safe dive time in freezing water
• No high pitched voice effect
• Works at depths up to 250 feet
• Causes no additional narcosis at shallow depths

Argonox is never used for deeper dives, because it becomes narcotic much faster than helium. For shallow cold water work however, it is the single best breathing gas available today.

Mountain rescue teams have also started testing argonox for high altitude operations. The dense gas works better in thin mountain air, and helps prevent cold weather lung damage during long rescue missions.

6. Artificial Hemoglobin: Oxygen Without Lungs

This alternative bypasses breathing entirely. Artificial hemoglobin compounds are injected directly into the bloodstream, where they carry oxygen to cells just like natural red blood cells.

These solutions were developed for emergency trauma situations when patients have lost too much blood, or cannot breathe on their own. One dose can keep a person alive for over 4 hours without any breathing at all, buying critical time for emergency surgery.

1. Requires no refrigeration, unlike donated blood
2. Works for all blood types with zero rejection risk
3. Can be stockpiled for 5+ years
4. Starts delivering oxygen within 60 seconds of injection

As of 2024, three different artificial hemoglobin products are approved for emergency use in the European Union, Canada and Australia. United States FDA approval is expected by 2026.

This technology will change emergency medicine forever. For car accidents, battlefield injuries and disaster response, this may end up saving more lives every year than defibrillators.

7. Chemical Oxygen Candles: Closed Environment Life Support

Oxygen candles don't store oxygen, they make it through a controlled chemical reaction when activated. These are the backup life support systems used on every commercial airplane, submarine and space station in operation today.

A single 5 pound oxygen candle can produce enough breathable oxygen for one person for 24 hours. They work perfectly even in zero gravity, underwater, or any other sealed environment with no external air supply.

Location	Number Of Candles Carried
Commercial Airliner	120 - 180
Nuclear Submarine	12,000+
International Space Station	420

Unlike compressed oxygen tanks, oxygen candles cannot leak, and they will sit dormant for 15 years or more with zero maintenance. You just strike the end like a match, and they start producing clean breathable oxygen immediately.

If you have ever seen the oxygen masks drop on an airplane, that air you are breathing comes from one of these candles. Most passengers never realize they aren't breathing from a tank at all.

8. Living Algae Systems: Closed Loop Oxygen

This is the only fully renewable oxygen alternative on this list. Specially bred strains of algae produce oxygen through photosynthesis, while absorbing the carbon dioxide that people breathe out.

NASA has tested closed loop algae systems for over 40 years for long duration space missions. A single 100 gallon tank of algae can produce enough oxygen for 4 people permanently, with no external supplies needed.

• Absorbs 100% of exhaled carbon dioxide
• Produces edible protein as a side product
• Requires only light and small amounts of water
• Will operate continuously for decades with no replacement

This is the system that will take humans to Mars. Compressed oxygen tanks only last for months, chemical candles only last for weeks, but a working algae system can keep a crew alive for years on end.

Researchers are also testing small home algae systems for indoor air quality. These small desktop units can clean the air in your home better than any HEPA filter, while producing fresh oxygen 24 hours a day.

Every one of these 8 alternatives for oxygen was developed to solve a specific problem that pure oxygen could not handle. None of them replace oxygen entirely, but each one adjusts, enhances or replaces standard oxygen delivery to work in environments that would otherwise be unlivable. What started as niche technology for divers and astronauts is now working its way into everyday hospitals, rescue operations and even home use.

Next time you take a breath of regular air, pause for a second to appreciate all the work that went into creating other ways to keep people alive. If you found this guide useful, share it with anyone interested in diving, emergency medicine or space exploration. You never know when understanding these systems might help you recognize the technology keeping people safe around you every day.