The helium method became widely used few years ago and is now in use by reputable organisations like Dignitas. (Edit: the helium method may have been used by Dignitas at some time in the past, but currently, Dignitas uses only a drink of 15 grams of pentobarbital sodium, trade name Nembutal). It is based on the fact that breathing inert gas like helium does not produce any feeling of suffocation but depletes the body of oxygen, leading to loss of consciousness and death.
Compared to other methods:
 How is inert gas asphyxia different from smothering?
Often, people confuse inert gas asphyxia with smothering (which is not peaceful at all).
 Feeling of suffocation: not enough air or too much CO2?
Everyone knows the unpleasant sensation when holding a breath for a long time. However, this sensation is not caused by lack of oxygen; the main factor is build-up of CO2 in blood. Even if our body constantly needs oxygen, it (surprisingly) does not have a mechanism to measure oxygen levels; instead, it relies on CO2 reflex to avoid asphyxia.
Under normal conditions, this reflex works reliably to protect us from high CO2 levels and from lack of oxygen at the same time: our body constantly produces CO2, so if we are unable to breath or are in area with not enough ventilation, CO2 levels rise causing unpleasant sensation. This is the sensation that forces you to grasp for air when diving in a swimming pool.
There is one special situation though: when we are able to freely breathe and exhale CO2, but there is no or not enough oxygen in the mix we inhale. Our body is not built to handle this situation well. When does this situation happen ?:
- breathing at a high altitude, where air pressure is low. One exhales CO2 freely but the body does not recieve enough oxygen. Because CO2 can be exhaled, CO2 reflex is not triggered, there is no suffocation feeling; often, consciousness is lost without any advance warning. Pilots are likely to face this situation in case of aircraft depressurization. Lack of warning before unconsciousness is so dangerous that US Air Force trains crews to recognize signs of approaching hypoxia.
- breathing a gas mix with low oxygen. In the next chapter, we focus on this case.
 Helium and other inert gases: free breathing, no oxygen
Many gases that are more or less nontoxic can cause asphyxia by replacing oxygen from the breathing mixture. as a result, they are dangerous in enclosed areas, but not otherwise. People start showing signs of asphyxia when the concentration of these gases is around 30 percent; severe symptoms at around 50 percent; death at around 75 percent.
Argon, helium, and nitrogen - are your best bets in this category. They are all tasteless, odorless, nonirritating, and under these conditions, chemically and physiologically inert. In fact, nitrogen comprises about 78 percent of the air we breathe. Since these inert gases are not poisonous and your lungs have something to inhale, such asphyxia will be minimally traumatic. That is, they will not cause feelings of suffocation (which are due to carbon dioxide buildup, not the lack of oxygen) or haemorrhages (caused by high blood pressure from blocked jugular vein or struggling to breathe against a closed airway).
Most medical use of inert gases is for animal euthanasia; however there have been human fatalities from them, too. For example, airline face masks were mistakenly hooked up to inert gas cylinders instead of to oxygen at least ten times during the 1980s in the United States. The fact that these people died without attracting attention is consistent with no traumatic death.
 Data and differences between the inert gases (pros and cons)
Helium (He) - The density of is 0.14 of the weight of the air we breath, which says it is just about 1/7 of the weight of the air we breath. That's why helium rises.
- Advantages: quite easy to get [will be discussed later], have been supported by most euthanasia books, and have many case reports to show success.
- Disadvantages: There were cases of failing the method [which we will discuss later]. Though most failures were due to crucial mistakes, yet it needed to take it into account. Another point = 96 the weight of helium and its inclination to rise, makes it crucial to plan your posture and position well when using it.
Nitrogen (N2) - a colourless, odourless and tasteless gas that makes up 78.09% (by volume) of the air we breathe. The weight of nitrogen is 0.97 of the weight of the air we breathe, which says it is just slightly lighter than air.
- Advantages: since nitrogen is 78% of the air we breathe, breathing this gas should be almost similar to breathing air, in terms of sense. Moreover, its weight being almost similar to the air, dispense of the need to address the possibility of this gas sinking down or rising up when we are unconscious.
- Disadvantages: Poor documented case reports. While this fact by itself does not say it will not be efficient, however, having case reports available may increase our sense of certainty.
Argon (Ar) - its specific weight is 1.39 times of the air's weight.
- Advantages: the gas is way heavier than the air so it sinks to the bottom of the chamber you use, so lying down when performing your attempt is a possibility.
- Disadvantages: poor case reports about it. the same statement about nitrogen is valid here too, that is, it says nothing about the method reliability.
 Where can you get inert gases?
Argon is commonly used for inert gas electric welding and helium for balloons. Nitrogen has a variety of uses and may be purchased either as a gas or as a cold (-196 degrees C or -321 degrees F) liquid. All of these are available from industrial gas suppliers. Helium can also be found at party-supply stores. Argon and nitrogen can be found at welding suppliers, or Heating, Ventilating, and Air Conditioning (HVAC) suppliers. None of these gases are dangerous unless they displace oxygen from the breathing mixture.
 How to generally use it (specific instructions are given later on)
Probably the easiest way to use inert gases for suicide is to enter a tube tent with a gas cylinder, flush the tent with any of the three gases, and seal the ends of the tube. The volume of a tent is such that you won't produce enough carbon dioxide to stimulate breathing reflexes before dying. Since there's little or no residual oxygen in the breathing mixture, minimal amounts of carbon dioxide ought to be exhaled, suggesting that a large inert gas-filled plastic bag over the head should work as well as the tube tent.
 The exit bag
Another variation of helium method uses an "exit bag", a plastic bag with attached hose. You can either order ready exit bag by post, or make your own one. There is a video demonstrating how to make an exit bag, available by purchasing the e-version of The Peaceful Pill Handbook.
Use of exit bag (from Final Exit by Derek Humphry):
Important note: in this image, the angle in which the person lies is not the recommended one by most known books (Dr. Nitschke, Dr. Admiraal). You would need to lie half sitting half lying.
 Risk of brain damage if rescued
The main hazard of this (and all) asphyxia is the possibility of brain damage if the process is interrupted due to intervention, running out of gas, or tearing or removing the gas mask, plastic bag, or tube tent while unconscious. Using a high concentration can minimize this of the anoxic gas, which causes most rapid loss of consciousness. These gases are not a danger to others in anything but a small, sealed space; however it's important that a gas cylinder not be mislabelled, lest it imperil subsequent users.
 Experiment with animals
In experiments, animals (dogs, cats, rabbits, mink, chickens) show little or no evidence of distress from inert gas asphyxia, become unconscious after one to two minutes, and die after about three to five minutes. Thus, use of any of these three gases, combined with a plastic bag, should be less traumatic than plastic bag asphyxia alone, since there will be little discomfort from carbon dioxide buildup and unconsciousness will be swift.
The following chapter is dealing mainly with helium due to extensive available track record with this inert gas; however, following this chapter, there is a section which makes adjustments regarding other inert gases.
 Cause of death
Inhalation of 100% pure helium (which is not mixed with oxygen) causes rapid death due to oxygen deprivation (since the helium displace the oxygen).when breathing pure helium inside a plastic bag, unconsciousness follows after about 5 breaths. In 62 cases where "time to unconsciousness" was reported, the average was 35 seconds (range 10-120 seconds). Death will often follow in about 10 minutes, sometimes as quickly as 5 minutes. Elapsed "time to death" was reported in 108 cases. The average was 13 minutes (range was 2 to 40 minutes).
 Advantages of using an inert gas
While breathing pure helium there is no feeling of suffocation or choking. This is because the breathing of helium permits the lungs to continue exhaling carbon dioxide (see remark 1).the brain never receives any warning signal of suffocation when breathing helium (or any other inert gas).[The Article: "analytical investigation in a death case by suffocation in an Argon atmosphere", in the magazine: Forensic science International. 2004].
Death by inhalation of Inert gas is not detectable through any known toxicity test. Only a witness or materials left in the scene can confirm helium inhalation as a cause of death. That's because helium rapidly dissipates into the surrounding air and does not remain in the body tissues or blood cells.
 THE METHOD
At least one organization sells a helium suicide kit. Tanks of helium can be purchased from toy stores.
 Lethal dose
According to the book Guide to a Humane Self-Chosen Death written by Dr. Pieter Admiraal and a committee of medical professionals, nearly in all 119 reported cases used non-refillable party balloon kits. A small tank [4.5 cu ft] is sufficient to bring about death if breathed in a plastic bag. To be sure, I would go for 8.9 cu ft [the following size].the assumptions are that the tank is new and full, and that there are no leaks in the bag.
 Sleeping pill
The book Final exit recommended taking few Valiums to contract convulsions and so; however, Dr. Admiraal from the Dutch euthanasia group says in his book that: "to be sure that one does not make any errors in the procedure, pills are not recommended". I tend to agree here with the Dutch booklet, since, falling into any sleep, may indeed cause you to act out of shallow or deep sleep, while you may take off the bag or miss some details. Case Reports regarding sleeping pills with helium in 31 reported cases, the patient took no meds at all. no complications were reported and time to death was not influenced.
The needed items:
- Helium tank.8.9 cu ft or more
- Oven roasting bag (19x24 Inch =45x60cm)
- Soft plastic hose/tubing 3 meters. The tubing must fit snugly over the tank nozzle. For most party balloon kits it requires tubing with an inner diameter of 3/8 or 5/16 inch
- A rubber band such as of tennis players
 How to adjust the hose to the tank and "make the set"
1. Take off the plastic nozzle of the tank. (Use any pillar for this) (You can also do it carefully with a carpet knife if you have trouble finding out what a pillar is) Edit: I think the author means pliers.
2. Put the edge of the plastic pipe in warm water for some minutes to make it softer.
3. Connect the hose to the tank and make sure it is very well adjusted. use a half inch hose clamp (you can get it in hardware stores) and adjust it with a screwdriver. If you're using a "Y"-tube for two tanks, remember to take the tube through the clamp before fitting the tube to the tank (if the clamp can't be opened).
4. Check the bag for holes or leaks. If you blow it with air you would be able to check in case it leaks.
 What if you buy the tank from other sources?
If you buy directly form a helium supplier, you should buy a regulator from them as well in order to control the gas flow. Never buy other than a new tank of helium, since you can never know otherwise if the tank is full. It is advisable by the Dutch euthanasia group to practice the procedure without helium so that you make sure you know exactly how to do it.
Note that testing is problematic; if you get one of the consumer helium tanks, you will most likely have a nozzle that won't shut completely, so if you perform a test of helium output with such a tank, you might eventually lose all of the helium before your actual exit date. However, a helium tank from a commercial helium supplier should not have this problem.
 The stepwise guide
1. The position: you have to sit or lean, such that your body is vertical, since the helium tends to rise.
2. Open the valve and close it immediately. that's for the first opening of the tank.
3. Place the bag on your head such that the margins of the bag cover only the ears and your forehead.
4. Now, the most important thing is to get the air out of the bag. If you have air there, you won't lose consciousness quickly. Most literature recommends doing it by squeezing the bag with both hands on your head to deplete the air. However, I suggest that this way there is a good option that air would be present.
Alternatively, you can simply put the bag on a flat surface, roll it back and forth to get all the air out and then you may close it tight, while leaving long enough margins (after the place where you close the bag with your hand tight), for placing the bag with the band,back on your forehead and ears. By doing so, you are more likely to get rid of all the air.
5. Now, open the valve and let the bag inflate with helium. You should now be prepared to pull the margins of the bag with the band over your head. The rubber should not be too tight since you need to leave some room for the CO2 you exhale, to get out of the bag through the bottom.
6. Now,VERY IMPORTANT: the Dutch group recommend here, to exhale all the air in your lungs BEFORE pulling the bag over you head. There is logic here, since you need to get rid of all CO2 in your lungs. So you need now to make a big exhale, then hold your breath, pull the inflated bag over your head with the band, and now, you should take a very deep breath(of the Helium in this inflated bag), when inside the bag.
7. Continue to breathe normally, unconsciousness should follow quite quickly.
 Statistics and case reports
According to Pieter Admiraal's book, in 119 reported successful cases using helium and a plastic bag: Nearly all cases used a non-refillable balloon kit, although, it is less reliable than any industrial size tank. In 62 cases where "time to unconsciousness" was measured and reported by an eyewitness, the average was 35 seconds [10-120 range] in cases where it took longer than average, it was reported that there were difficulties with gas flow, Leaking tube/nozzle connections, or improper seal between the neck and the bag. That's why a good preparation is needed, says the Dutch group.
 If using a T-connector instead of a flow regulator
If using a T-shaped connector to join the flow of two disposable helium tanks, make sure to use one made of PLASTIC or VINYL. A T-connector is often sold as a "hose barb" or a "garden hose tee". The right size (if using tubing of 1/2" OD and 1/8" ID) is 1/8" OD so the tubing will fit OVER the T-connector perfectly. T-connectors look something like this: http://i.imgur.com/piqQo.jpg. Often sold in the PVC isle of a hardware store.
 Time of death info
Time to death was reported in 108 cases --- the average was 13 minutes [range 2-40 minutes]. Muscle contractions were reported in half the case reports. it happened between 2 to 8 minutes into the procedure. Arms and legs will tighten and relax few times for about 10seconds to 2 minutes duration. It is not should be interpreted as an attempt to remove the bag. Those contractions are common in anesthesia in surgery settings. Witnesses of several cases with helium said that they have never seen a case in which the hands reached the plastic bag. Patient is unconscious in this stage. Deep gasps are common in the unconscious stage. In 31 cases in which no meds were in used it was found that there is no correlation between meds and contractions. In 11 cases contraction have been present while in 7 non were present.
 Reports of failures:analysis of the causes,and insights of how to avoid it
 Report on failure - #1
Source: this ASM thread
"Speaking from experience, I can say that helium is not as comfortable as it sounds. Breathing it was not a problem. However, moments after beginning, my whole body started feeling all tingly (like a foot that has fallen asleep or something). After that, body started having uncontrollable convulsions. Finally reached up and removed the plastic bag. I was a bright shade of pink for a while after the experience, which I found out later, was a symptom of oxygen deprivation. Was no pain, just a very uncomfortable feeling "
Explanations: What might have happened?
The man describes what he has done: "What I had done, was place the bag over my whole head/face, ran the hoses up into it, pulled the rubber band down around my neck, and held the rubber bands away from my neck to continue breathing air until I was ready."
Mistakes done: That means he had a good breath of air in his lungs when went went in (as he DID NOT exhale first as he should, in order to deplete the lungs from CO2). Moreover -- there was probably quite a bit of oxygen in the bag as well, since the man did not emptied the bag BEFORE streaming helium in.
General inferences, following that case:
The main goal when using an inert gas, is to have a sudden and intense exposure to the gas. You need to make the best you can to make sure that no oxygen or carbon dioxide is in there to contaminate the helium, with your first few intakes of breath you will be inhaling nearly-pure helium. This is what is required for a quick loss of consciousness. if you proceed by piping helium into a bag (or tent) which currently contains air, that would be quite disastrous -- for a long time there would be enough oxygen to support consciousness, and that consciousness would become very unpleasant before it vanished.
 Report of a failure - #2
Quote: "I really tried the helium method as described in the Dutch booklet, and really wanted to go. Before dragging the bag on my head I was even excited and happy that finally all my misery and illness will be history. So with the full of helium bag on my head I started to breathe normally waiting to lose consciousness in 2-5 breaths. Instead of that, after some 15 deep breaths of helium all I felt was pain in my chest, my heart pounding like hell and a HUGE panic. It was everything but pleasant or peaceful. So, I couldn't resist that overwhelming feelings and took the thing of. It took some 10 min. to get back completely. I felt dizzy and had a light headache. I was hoping I didn't damage my brain. What I want to emphasize for you is that this method is not so peaceful as I would have thought."
Explanations: What might have happened?
I knew of one other person who did not lose consciousness quickly and who felt significant panic (enough to make her stop). In her case I think it may have been because the helium was contaminated with oxygen-containing room air. She wanted to use 3 tanks, to be sure that the helium would not run out too soon, but she joined the various tubing pieces with T- connectors intended for use with copper plumbing pipe. These connectors went on the outside of the tubing rather than on the inside (she had not managed to find the kind that goes inside the tubing, and the hardware- store person told her that the plumbing connectors would be just as good). She put lots of tape over each place where a connector lay over the tubing, but she used electrical tape, which does not have a high degree of stickiness (not as high as duct tape, for instance). There were quite a few of these possibly-leaky connections, and I think that perhaps wherever the helium flowed past a connection it entrained (pulled in) some room air.
Also, this above person may have skipped thoroughly forcing all room air out of the bag before filling it with helium, and thoroughly evacuate the lungs by doing a big "Whoof!" immediately before pulling the bag down.
If the first thing is not done, there can be quite a bit of oxygen in the bag, and if the second thing is not done, there can be quite a bit of carbon dioxide; breathing carbon dioxide causes panic. However, panic can accompany rapid loss of consciousness even in the (relative) absence of carbon dioxide (I felt it when I passed out from ether, though only for a couple of seconds).
 Report of a failure - #3
Source: | this message 11-8-2006
"I recently tried the helium + plastic bag, and I failed. I bought a 20 l helium tank and some big plastic trash bags. The first problem I experienced was that the tank was huge. And I didn't have any tube to connect it to the bag. So I tried a few methods. I first tried lying in bed (slightly upwards so that the helium would concentrate at the top) and had the top part of the tank inside the bag along with my upper body. I closed the bottom part of the bag pretty well to prevent leakage. I had the helium tank running for a little while and my head started to get dizzy, but quickly panic stepped in. I tried to wait it out, but in the end I just couldn't. Anyway, I thought maybe the bag was too contaminated with oxygen, and that's why I kept getting the panic attacks (quick heartbeat etc). So I tried to fill the bag with helium before I actually put it over my head. Then I put it over my head ... same result, although, it lasted longer in that attempt, probably because there was less helium in the bag. I tried a few different postures with the bag over my head and the tank inside, but nothing seemed to work. At the end I was feeling very dizzy, but I just couldn't go through with it. Could anyone give me some advice? I thought this method was supposed to be foolproof and painless, but it just wasn't for me. I felt the same way that I feel when I put a plastic bag over my head and no helium, the panic and increased heart rate steps in pretty quick."
Explanations: What might have happened?
When somebody does not lose conscious shortly, it is due to excess of oxygen in the bag. It usually happen when the bag is not previously completely depleted out of all the air. That should be done before any helium is blown into the bag. Residual oxygen will make you experience the side effects. Now, as to the panic itself, I would attribute it to a CO2 build up. One should not complexly close the marginal of the bag, and only use a slightly tightened band, to let the CO2 escape form the bottom. During the first attempt, this guy got into a kind of a "tent". This imposes a problem since you have large amount of oxygen there, and you need to either deplete it first, or to create a very strong and steady stream for that.
 Report of a failure - #4
Source: An ASM message in this thread
Oct. 2004 "I tried this recently. I panicked while nearly passed out and took the bag off, although I only vaguely remember doing it. I used a tank with 15 cubic feet of helium. In the U.S. (at least here in California) you can get these at Party stores. So be sure you take something to relax you or make you sleepy, and be sure that the helium is turned up high enough to keep the bag from getting warm and moist and hitting your face, which is what caused my state of panic. You will start breathing heavily as your body starves for oxygen. I suspect if I'd been in there another 15 seconds I would not have been able to undo it."
Explanations: What might have happened?
14.9 cu ft of helium should be well sufficient for succeeding. While Final Exit recommends 1-2 tanks of 9 cu. feet, it was proven that even 4.9 cu ft should be enough. moreover, the Dutch euthanasia group, recommended, following more than 120 case reports, to avoid using more than one tank, since there is a great chance that the connectors would create a leak, if you use more than one tank. It is indeed recommended to make sure the regulator of the tank is at least turned to a one third [full guide is given] to allow sufficient flow of helium. However, using sedatives is not recommended in this method as it may increase the chances to fail, as you are likely to miss some of the accurate instructions if so. The moist and heat in the bag should be prevented once you open the valve sufficiently as instructed.
 Report of a failure - #5
July 2007, a report of M.D. :
"In the one case of which I have knowledge, there were many difficulties. The size of the tube that was given did not fit the fixture and, at the last moment, had to be reamed out with a makeshift tool. The valve was very hard to open and knuckles were slashed on the sharp handle of the tank as the struggle to open it ensued.
"The patient appeared to fall asleep readily and in seconds, but after about a minute eyes opened and the patient sat up slightly and breathed shallowly and extremely rapidly (over 200/minute) for ten to fifteen seconds. This occurred three times. After that, both upper and lower extremities flailed about for fifteen seconds or so. Then, after a few minutes pause, this happened again. Then once again, the movements did not conform to any pattern. The eyes were partially open and it could not be determined if there was any consciousness.
"The whole process took about fifteen minutes and was horrifying to the onlooker. The person who had given the verbal instructions for the procedure thought it might be due to the fact that the patient was, due to chronic respiratory difficulty, unable to take a deep breath and exhale at the right moment, but subsequent discussions with anesthesiologists cast great doubt on this notion as total anoxia must have occurred long before much of the seizure like behavior even if not quite as quickly as with a good exhalation. Also, the question was raised if the pacemaker- defibrillator had produced some of the effects, but discussions with cardiologists tended to rule that out as the amount of current was deemed to be too low to produce seizure. Apparently, from some of the current mailings, the helium Method is not the ideal exit that it's touted to be. Norman J Ackerman, M.D."
Explanations: What might have happened?
The first part can easily be dismissed as not ensuring everything would go off without a hitch, but the actual account of it seems disturbing. I know, I shouldn't be surprised it's not a party, but still.
I might be wrong, but this seems to lead to only one conclusion, that oxygen was leaping in from somewhere.
That seizures during the process are likely to occur seems to be inevitable, the question is, is the person aware of them or in any pain, when it happens (patient should be unconscious in that point)?
If a mask has been used it tends to be less effective in this method. The origin of the helium is another factor which may be missing.
 Report of a failure - #6
Source: | ASM message
"I failed with helium today. I never passed out; I just got light headed and experienced tingling and numbness in my hands/arms. What I used: 99% Pure helium 14.9 cubic feet tank > tube > plastic bag 2ft x 7 ft non- rebreathable medical mask > tube ----------^
"I should have had enough helium pumping into that bag to do the job but I am still here and I never passed out so something went wrong. My best guess is either (despite the amount of tape I used) there was a leak somewhere on the bag (does helium escape particularly easily?), or the mask wasn't doing its job properly and letting air in. Can anyone help me out with ideas of how to make this work? I have thought about a small tent but after this failed attempt I have a feeling the helium would escape extremely easily. I can't just do it straight from the tank to a mask because there isn't enough helium, I need to contain the helium in something and make sure I waste as little of it as possible. A regular plastic bag over my head wouldn't hold enough either."
Explanations: What might have happened?
Indeed, helium "escapes" quite quickly in any open space or such as not sealed well enough. Thus any possible leak, either in the tube or in any mask or so, may be a reason for such a failure. In addition, again, the man has not lost conscious, probably due to remnants of oxygen penetrating to the mask. That's why I would say a closed chamber would be better. [for this term, a plastic bag would be considered as a chamber of course]
Suggestion: I've heard people purchased the party balloon tanks only to find out when they got them home that the package had already been opened, and when used, found it to be empty. The problem here maybe returned tanks going back on the shelves. So check the package to see its been opened before, make sure its in a sealed box! You could also do a one balloon test. Tell the store you are purchasing it but want to make sure its not leaking, with permission open the valve, blow up one baloon.. if it fills quickly its working the way it should, tanks with leaks would fill a balloon slowly. Tighten the valve very tight once you are through.
 FAQ and common discussions
An average person will breathe in and out about 12 to 20 times a minute . People who are tall and/or overweight will breathe more than someone who is short and/or thin (based on Body Surface Area, BSA). Each inhalation brings in about 500 ml of air, corresponding to 6 to 10 litres of air per minute, together with any contaminants that the air contains. Please note that people who smoke, and/or have pulmonary sickness will breathe almost 2-3 times more air than an average person.
In an average person, the respiratory rate in cubic feet per minute is (worst-case):
For a helium tank containing 14.9 cubic feet of helium, the tank should last:
For someone with asthma, or heart disease:
Making the 14.8 cu ft helium tank last:
 Which purity of helium is needed?
Q: How important is the purity of the helium, and what's acceptable?
A: In general terms, balloon-grade helium is sufficient to cause death if it is the only gas an individual is breathing. Any gas that contains no oxygen will kill you if it's all you're breathing, but some gasses trigger unpleasant responses What is the concern about CO2 in this method? While it's true that any gas mixture without oxygen will black you out pretty quick, I need to add a minor correction about CO2: At concentrations > 30%, CO2 will drop you with little or no warning, even with 'normal' levels of oxygen. At higher concentrations, CO2 acts like an anesthetic and then kills rapidly. The 'unpleasant' effects all come from lower concentrations of CO2. CO2 kills unwary people all the time, including people who deliver it for soft drink fountains, people who hang out in low places near volcanic activity, people who work with agricultural waste, people who work in grain silos, people in coal mines, and people unfortunate enough to be near places like Lake Nyos when it gassed over. In most such cases, they were 'fine' one moment, and unconscious the next.
 But if the helium runs out wouldn't I suffocate?
A: In a sealed-in area, yes you would, eventually. But you'd be more likely to suffocate from CO2 instead of helium, and CO2 suffocation - at least at a slower rates of air infusion - can be very unpleasant. The body's evolved some rather nasty responses to CO2 poisoning because it's a kind of poisoning virtually all oxygen-breathing mammals are prone to - choking, suffocation, etc.... The body has learned when CO2 levels increase, it needs to do whatever it can to make you breathe harder or clear your breathing passages, and so you convulse and cramp in all sorts of nasty, painful ways, Unless of course you can get just about immediately into a very high- concentration of CO2 quickly, where it can drop you pretty fast. But bags over the head relying on CO2 to do the job don't tend to work that well. The body has learned no such response to helium, and while in the early stages of helium, the body can still release CO2 for a time. More so than to acquire oxygen, the primary functions of breathing is to release CO2 from the body. It's the pressure to release CO2 that causes that "I thought my chest was going to explode" feeling in near-drowning victims. Acquiring oxygen is a secondary function of breathing - just as vital, but as strange as it may sound, you can survive longer without oxygen coming into your body than you can without being able to release CO2 (which you can't do if CO2 is what you're breathing - at best, you're shuffling individual CO2 molecules around, and the body doesn't know the difference between one that's already been through and one that's just arriving). Both functions are vital, of course, and we'd die in fairly short-order without the ability to do either one. But CO2 poisoning is the more critical issue to the body, which is why the body reacts to CO2 gas but not to certain other kinds of gas. Other inert, non-irritating gasses allow the continued release of CO2 for a time, which keeps the body off- guard for awhile. With those types of gasses, it's too late for the body to react by the time it realizes it's not receiving any more oxygen.
 Q: How is removing CO2 going to kill you?
A: If you mean tanks that aren't filled O2, but rather nitrous oxide or helium, then there's no need for scrubbing out CO2. Helium doesn't become CHe when inhaled, it stays helium. Same with nitrous oxide. Your body doesn't convert the gas at all. The same breath of helium can be used over and over until you're dead.
 Q: What final exit says and what's missing there?
A: The book (I sprung for it finally after failing) suggests running a tube from the helium tank to a plastic bag which is positioned on top of your head with a rubber band or such around your forehead to hold the bag in place. Let the bag fill with helium, EXHALE, and then pull the bag down over your face positioning the rubber band around your neck to hold it in place.
 Q: Some issues which may arise when buying the balloon kit tank?
A: The gas tanks that are supplied for filling balloons have an unusual outlet. It consists of a spring-loaded nozzle, which when bent, opens a valve to allow the gas out. Filling the balloon in a matter of seconds. When the nozzle is released, the spring forces the nozzle back to the horizontal position and the metal plunger slides back against a stop, cutting off the gas flow. There is a master valve on the top of the cylinder too, but it doesn't allow for much flow regulation. In that case we recommend on getting a proper gas regulator valve, to replace the one on the cylinder. This is one of the reasons I prefer obtaining a proper helium gas directly from the helium supplier (all gas agencies would sell it to you).if they ask you why do you need it, you can obviously say you are starting maybe a party line, and you'd like to first buy a small tank [14.9 cu ft or so]to test is in a private party, "to see how it goes". Most suppliers will offer the regulator immediately, thus preventing the extra hassle of taking care of it.
 Q: what is most important to take care of before pulling the bag over the head?
A: It is important to make sure there's no air in the bag or in your lungs before starting. having air in the bag would interfere with losing conscious while having air in your lungs would cause panic attack due to CO2 build up.