Marc's Public Blog - Public

If it's too much text, here's the summary: this is a lipo safe pouch that you can stick your phone or a lithium powered device in if it starts getting hot and/or making smoke, while you get the hell out of your chamber ASAP. Buy one as extra safety and you should be fine with your phone as long as it's not a really cheap knockoff with a bad battery that you're not charging to 100% just before getting in the chamber. However, you do want to read this page about the risk of static electricity from clothing which is non zero, even in soft chambers that are around 30% O2 inside.

Science and research, matter

Before explaining how using lithium and lipos in an HBOT chamber can be about as safe as it's safe to walk on a tropical island without being hit by a coconut (it happens, but it's very rare), I need to explain why I even felt the need to write this: the answer is sadly that I'm spending this time beccuase Mr Jason Sonner did not spend just a little bit of time researching his claims about cell phones in chambers before making sweeping and wrong statements in one of this videos and telling everyone not to ever bring phones in any chamber (even 1.3 ATA soft chambers).

Anyone interested in HBOT probably has seen Mr Jason Sonner's videos on youtube (from HBOT USA). First, I want to be clear that he is not a medical doctor, and he calls himself Dr Sonner to give his voice more credit/importance. I do find that annoying, but in the US there are many ways to call yourself a doctor without being a real doctor (medical doctor). Basically, with a PhD in computer science, I can call myself a doctor too, when I'm obviously not a real doctor, in this case any more than Mr Sonner. Now that this pet peeve is out of the way, let's carry on.
Since real credentials do matter, instead of fake doctor credentials, I will state that have a dual major in electronics and computer science (which is relevant for the cell phone issue), I'm also a nitrox water diver (relevant for dive tables, altitude diving and flying after diving), and I'm also an airplane pilot (so indeed I know about how planes are pressurized). Sadly Mr Sonners talked about all these topics and was wrong about all of them. Actually I have one more "certification", I'm also an RC plane builder and pilot, so I have plenty of experience with lipo battery crashes and fires, personal experience even that I will give below.
And now I also have to add that I'm not actually a fire in enriched air environment expert, so I used google gemini AI to fill in my gaps in expertise and have updated this page to better explain the much higher consequences of fires and flamability in 30% O2 rich environment at up to double the normal pressure.

Mr Sonner puts a lot of youtube videos to generate income from youtube and advertise his program/services. Honestly, that's fine and I'll even say that a fair amount of his content is helpful and useful. I also do believe that at times, he is careful about what he states, but my personal opinion now is that he has started to overdo the amount of videos he does to keep getting more youtube traffic and does not sufficiently research some of the claims he makes. He then states completely incorrect things with the same convincing straight face, which is a problem. More annoyingly I have never seen him take any of the factual corrections given to him when he makes mistakes, and never seen him correct or amend a video. As a result, this completely eroded the trust I put in him initially and I can't just believe anything he says anymore and I do believe he cares more about getting traffic and selling his course, than giving correct advice at all times possible or being honest if he does not know instead of making things up.

So you're going to ask me to give a few examples of very wrong claims he made:

In one of his videos about flying after HBOT, he stated as facts how long you had to wait before flying as just random guesses based on no data whatsoever. The fact is that real divers, the one that go in water, and I'm one of them, already have diving tables about flying at altitude, like being able to dive 10 meters deep in a lake at 2500 meters altitude (or 8000ft more or less). Guess that, that's actually the same as a 2.0 ATA HBOT session and going into a plane immediately as soon as you get out of the chamber. Those tables exist, you can immediately go in a plane as long as your dive wasn't too long. And in the case of a mere 1.3 ATA chamber, the nitrogen loading is that much lesser even that flying after hbot is not anywhere close to a being a problem. I pointed that out to him in this video at the time, he never made any correction and the video with wrong advice was still up last I checked.

In a more recent video about recent HBOT accidents, he falsely claims that plane cargo holds are at a different pressure than the passenger cabin (I'm assuming he thinks unpressurized). This is totally untrue, the entire plane is a tube at the same pressure (I'm a pilot, I know, and honestly what would happen to the poor animals that go in the cargo hold if it wasn't pressurized). Gross mistake showing he didn't even think about it one minute, never mind researched it

Then he also makes up some BS advice about what charger you're using to charge your phone and that the wrong charger could "overcharge" your phone or "charge it too quickly". This is not how those things work: phones regulate their state of charge and speed of charge themselves and all a charge can do is not being able to deliver as much power as the phone would like to. A bad charger will fail to deliver enough power and slow down the charge or shut down. Technically an absolutely evil charger could be designed to send the wrong voltage and fry the phone, but that's about it.

After that, he goes saying that the repeated pressure changes applied to a phone going to an HBOT chamber, cannot be safe for a phone over time, which is just a random wild guess based on nothing. If he had researched it a bit, pilots and flight attendants take phones every single day at minus -0.3 ATA (same differentia as 1.3 ATA HBOT just the other way around) and nothing really happens because they can take it. Now, if you think about it, -0.3 ATA (a plane) is actually a bit worse for a battery as it could cause the battery to expand under lower pressure and potentially hit a sharp edge, sever the protective pouch and that could cause a fire. I personally believe this was a indeed a contributing factor to the samsung note 7 fire accidents (see below for details)

The risks with lithium/lipo batteries

Now, instead of just stating facts with "trust me, I know what I'm talking about", I'm going to explain the issue with lithium/lipo (lithium polymer) batteries.

I crashed this RC plane into a pole in flight, it damaged the front of the plane from the impact:

I drove the plane home, took the battery out, and worked in my garage. The battery self ignited 10mn later while I was thankfully there to throw it on the floor and let it burn out. Yes, this means had this happened at the wrong time, that fire could have been in my car. I have also read about RC pilots having their fridge destroyed by a lipo fire (we store lipos in the fridge as it extends their life).

So what went wrong? It was a cheap lipo battery, the heavy deceleration (flying speed to immediate stop) compressed the battery internally, caused a failure of its protective envelope, air got in, and air causes lithium to self ignite, which it did.

Now let's look at another example, this RC plane crashed into the ground at terminal velocity. Its more expensive lipo was heavily impacted, but the protective envelope did not fail and it never caught fire. I did keep it a few days for confirmation, then discharged it and got rid of it since I don't want my garage to burn down in case it still failed later, I was honestly positively impressed that this lipo survived the crash:

Now, let's look at the well known Samsung Note 7 what would catch fire. There is a full analysis on the accident chain and what happened is Samsung tried to fit a bigger battery to improve runtime, they tested that, and before shipping their vendor didn't have enough batteries so they used a second vendor to help, but that second vendor had slightly different batteries that would bulge under certain charging conditions. Then Samsung did not leave enough breathing room around the battery and left a sharp edge on the circuit board which could puncture the battery when it bulged. And there you go, battery fire:

So, how about you and your phones/electronics in an HBOT chamber, is it safe? Mr Sonner says "no way, don't do it". Obviously no one can sue him for saying that, but at the same time, people are less likely to do HBOT treatments if they have to with special clothing and with only a paper book or pencil and piece of paper, like full O2 chambers require. I'm writing this page for people using long term HBOT at home, so it has to be bearable for long term use.

Flamability of 100% O2 chambers vs 30% O2 soft chambers, risk of clothing may be higher than phones

So, let me indeed start with this. If you are in one of those medical hard chambers at 2.0 ATA or more that do not use a mask but put 100% O2 in the chamber, those are the only ones not to f. around with. These chambers are dangerous: any spark, even from static electricity (hence you being restricted on what clothing you can wear), can cause a fire which in 100% O2 will be a disaster. 3 Astronauts for a lunar mission died quickly from such a fire on the ground during a training from a short and fire in that 100% O2 environment. So if you are in one those chambers, sorry, no phones, no nothing. Do whatever the staff tells you, it's no joke.

For everyone else, including all the soft chambers and generally any chamber where you are breathing around 90% O2 via a mask, some of that O2 will leak in the chamber, but the chamber air is also constantly being replaced. What this means is that while it won't be 21% O2 in the chamber, the math to calculate the actual O2 concentration in the chamber is a bit difficult, but when I had gemini google AI do its best estimate, it guessed that the Olive compressor may only output around 70lpm in the chamber (due to back pressure) and that the chamber will end up with 30% O2. I reviewed the AI's math and assumptions, and they look correct (sadly in the direction of a higher risk that my gut feeling originally perceived)
This is were I will avoid making the same mistake as Mr Sonner, as I was going to say next that 30% instead of 21% doesn't feel so bad, but research showed me that there is some kind of runaway effect for fires past 23.5% O2 that makes things burn much better, and materials that won't burn in normal air will suddenly start to burn well. The other factor I almost forgot is that you have to add 0.7 ATA of extra pressure over sea level, which means 70% more air molecules which in turn contain 7% more oxygen. If you add those 2 together, you more or less have twice as many O2 molecules available in the chamber to make things burn. This is "not good" as far as fires go.

At this point, I have to correct my original feeling that fire risk in a soft chamber wasn't nearly as bad as a 100% O2 chamber and say that in a 30% O2 chamber, the risk still seems bad enough that a fire in a 30% O2 soft chamber can end up being just as fatal as in a 100% O2 chamber. The difference between the two is how likely a static electricity spark is to ignite your own clothes (which now has nothing to do with electronics or phones anymore). Because I have never heard of a single fire in a chamber due to self ignition of clothes in a 30% O2 chamber, for now I'm going to assume that it remains very low, but please don't bring in your sweater that makes sparks.

And now, I will give the longer answer from Gemini AI:
Yes, the risk of static electricity sparks igniting clothing remains a severe and highly regulated hazard at a 30% oxygen concentration. While 30% is less concentrated than 100%, it still falls well above the 23.5% threshold that international safety organizations (like OSHA and the NFPA) use to define an "Oxygen-Enriched Atmosphere" (OEA).

Because of this, the strict clothing restrictions applied in 100% O2 environments generally still apply or should still apply to environments hovering around 30% O2.

The Physics of Static Sparks and 30% Oxygen: To understand why static electricity is still so dangerous at 30%, we must look at a metric called Minimum Ignition Energy (MIE). MIE is the smallest amount of energy (like a static spark) required to ignite a combustible material:

In normal air (21% O2): It takes a relatively large spark to ignite everyday clothing. Synthetic fabrics (like polyester or nylon) generate a lot of static electricity when they rub together, but the sparks they produce usually do not contain enough energy to start a fire in normal air.

In enriched air (30% O2): The MIE of almost all materials drops drastically. A static spark that is completely harmless in normal air now possesses more than enough energy to ignite fabric.

Because of the lowered MIE and the rapid spread of fire in a 30% O2 environment, the following clothing rules are standard for any hyperbaric chamber operating above 23.5% oxygen:
Strictly No Synthetics: Materials like nylon, polyester, rayon, and spandex are strictly prohibited. These materials are notorious for generating high static charges (triboelectric charging) through simple movements, like shifting on a mattress.

100% Cotton Requirement: Patients are usually required to wear 100% cotton clothing. Cotton naturally holds a small amount of moisture, which makes it less prone to generating static electricity.

No Petroleum/Oil-Based Products: Lotions, hair gels, and makeup can become highly volatile in a 30% O2 environment and can be easily ignited by a static spark from clothing.

The "Slight Enrichment" Hazard:
It is a common misconception that fire risks scale purely linearly from 21% up to 100%. In reality, the most drastic changes in flammability happen in the initial jump from 21% to 30%. Research on hyperbaric safety indicates that materials only require slight to moderate enrichment to support violent combustion. If a static spark from a polyester shirt ignites the fabric at 30% oxygen and 1.7 ATA, the resulting fire will burn significantly faster and hotter than it would outside the chamber.

That last bit went against my initial gut feeling, so I am duly corrected. I will however add that the air cooler for my chamber tends to pump moisture in my chamber, making the air more wet. The Gemini AI forgot to consider that bit until I prompted it, and basically the wetter air makes it much less likely for my clothing to generate sparks (while I do remember in California's Tahoe snow resort hotels, the dry air is so dry that I've seen lightening sparks between bed sheets at night when moving them the wrong way, both cool but slightly scary to see in the dark at night).

Managing and containing fire risk

The previous point has educated me (and now you) that surviving a fire in even a 30% O2 soft chamber, is not the best odds, ever. If you have something that starts actually burning in a chamber, I have to be honest and say that it could get bad quicker than you may be able to exit the chamber. The good news is that lithium batteries will typically bulge and emit smoke before just bursting into flames. And now you know that if anything is looking remotely wrong with your phone inside a chamber, you immediately put it in the lipo safe bag, close it, and exit the chamber.

From here you can apply common sense:

if you still have a samsung note 7, yes, don't bring that phone in a chamber, or in a plane, or honestly just get rid of it. This is also valid for any no name phone you got at an incredibly low price in some dodgy place. If it's not a reputable phone, you don't know how cheap the battery is (go back to my above pictures of the 2 RC plane crashes and different outcomes because of the battery quality).

Similarly, don't bring in cheap non essential electronics that could somehow create sparks or have a battery that shorts or get punctured. I'm not going to give you a list, apply common sense.

I have personally tested almost every google android phone made in the last 20 years. I have had 2 where the battery bulged enough to separate the phone. One was because I kept it charged at 100% while hot under a car windshield on a long road trip. This is a worst case scenario for the battery and it bulged but never smoked or caught fire. I did have to replace the phone though as it was not safe to use after that. Moral of that story, don't keep your battery charged and charging at 100% in harsh environments.

power banks can be problematic, there is a race to the bottom on making the highest capacity powerbank at the lowest price. You can guess that some of them have cut corners on safety. They are a risk on planes and plane crews are equipped to deal with powerbank smoke and fires, but overall airlines are less and less happy with you taking powerbanks. You don't have a good reason to need a powerbank in a chamber, it's only 1h or so, so don't bring one.

laptops, well I have taken mine a few times. You probably don't need to, and do not bring any laptop that has a spinning hard drive. It won't catch fire, but those drives have an air hole and a delicate thin air cushion the read/write head flies over. Changing the air pressure significantly can cause the head to crash and destroy the hard drive. Almost all recent computers have flash storage now so it's not an issue for them.

Properly made phones really should be fine. If they safe enough for a plane, they should be safe enough for HBOT with soft chambers. The one thing you now know though is that unfortunately a failure in a chamber has much higher consequences than in a plane (the plane air is also 33% less dense and less flammable as a result)

Basically the very small risk of a lithium battery failing (remember it is extremely rare because each time this happens in an airliner, it's still a big deal) is almost always after one of:

during or soon after charging (and worse if it's done in hot conditions)

when you've charged past 80%

after a serious high impact shock or crushing your phone in your electric airline seat, which won't happen in a chamber

So when taking phones into a chamber, stick to these rules

don't charge your phone full right before going in the chamber and above all things do not charge your phone inside the chamber, ever (you'll have noticed the airliners also ask you not to charge powerbanks plane anymore, it's for the same reason)

generally if your phone allows charging to 80%, use that for the longevity of your battery and decreasing the risks of bulging

it's a good idea to bring a fire proof lipo safe bag inside the chamber and if your phone ever starts making smoke, immediately put it in the lipo safe back, close it, and get out.

was your phone just in a heavy crash? well, that is the one time where it might not be super safe anymore, so if the phone was not visibly destroyed, keep in mind the battery could be compromised, and I would not take that phone in a chamber or plane anymore.

learn how to exit your chamber as quickly as possible although still use the decompress valve, if you just open the zipper directly under pressure you will likely damage the chamber. Then again, if it's on fire, screw the zipper, just get out as quickly as possible.

This is a lipo safe pouch that you can stick your phone or a lithium powered device in if it starts getting hot and/or making smoke, while you get the hell out of your chamber ASAP:

And I'll end with being honest and giving the worst case scenario which ironically is actually the one I'm in. I have the Olive Oxyair 2.0 ATA capable soft chamber (read my report here on why I bought it and why I think it's the best soft chamber on the market)

This chamber:

goes to 2.0 ATA, so that's more pressure change for a battery, but I also said earlier that compressing the battery should not be as unsafe as putting it in a low pressure environment

however 1.7 or 2.0 ATA while better for many HBOT treatments is also a lot more O2 fuel to help a fire, both because the higher pressure means lower rate of air replacement in the chamber and higher pressure means more air molecules available for a fire.

this chamber uses seat belts that have to be unclipped one by one to get out. You need to at least unclip 3 to get out making a quick exit definitely slower (I estimate up to 10 seconds slower).

So in my case if I had a catastrophic situation, it would likely take me at least 20 seconds to get out, by damaging the zippers and chamber by doing an emergency opening without equalizing first, and then unclipping 3 seat belts before I can get out which I can do that while holding my breath if smoke is an issue. I initially stated that 20 seconds was fast enough to get out in case of an actual fire, but now I have to amend that to say that actually in that up to 30% O2 rich environment, those 20 seconds will actually be very long, so I really don't want an actual fire to start while I'm in the chamber.

Conclusions

Should Mr Sonner ever read this page: yes it took a lot longer to research and write this page than it takes him make the average quick youtube video meant to bring traffic and ad revenue, but details do matter, so please take the time to do proper research. And while I was originally a bit upset that I spent this time just to correct one of his videos that he put out way too quickly and with too much misinformation, in the end, I actually learned additional things that were worthwhile to me and everyone else while writing it.

Is taking your phone in the chamber 10000% safe? No, nothing is, but my perception of this risk is that it's in the 0.001% range or less. No, I can't back up this number, but hopefully the info I gave in this page can help you decide if that risk is smaller than being in a car accident, which I personally believe it is. I hopefully also conveyed my personal opinion is that risk of fire from the wrong clothing is higher than risk from a phone, and if your clothing or hair do catch fire, even in a soft chamber at 30% O2 and up to double sea level pressure (hence twice as many O2 molecules available for burning), it's very bad news.

I'll also add that the lipo guard bag is more an additional safety for something that really should not happen to start with, taking your phone in a soft chamber without a lipo safe bag is not completely stupid, the odds of anything happening to your phone are just super low, but given how catastrophic a real fire can be in a chamber, I would definitely have the lipo safe bag to shove your phone in and close it if anything starts looking bad with the phone.