• Lee Bird
    Hi Team,

    A bit of background first:

    Last week I was asked to help a client with a serious harm injury involving a 17 year old apprentice with serious burns to his left arm and side, when I asked the boss "roughly what happened?" he replied shakily "He only opened the oxygen bottle and it exploded!"

    I'm a fitter by trade with 20 years in various industries so straight off the top of my head I thought the boy has done something he shouldn't have, grease on the hand, improper installation, leaking bottle something obvious surely.

    I was then shown a video clip found by the employers father, which opened my eyes and took me completely by surprise (links further down)

    Further investigation is confirming the cause as: ADIABATIC COMPRESSION in the Oxygen regulator unit.

    Never heard of it? Neither had I, however its more common than you might think not only this, without very simple controls in place has the ability to happen in many of the Oxygen regulators sold off the shelf in any part of the country by reputable suppliers, and unbeknownst to the consumer.

    So here we go:

    Some Oxygen bottle regulator units have aluminium in the valve body, some in the medical industry for weight purposes however many are sold off the shelf by reputable welding suppliers for cost reasons.

    The better quality regulators available are solid brass. Remember one thing here, my client has never walked into any shop and asked for the cheapest price on his gear, this was sold straight off the shelf as a first and typically only option, most frontline staff are blissfully unaware of this risk and naturally assume the lower the cost, the better they look and the more business they get, not silly at all.

    The difference? Aluminium is a flammable metal, its ignition temperature is much easier to achieve than other metals able to be used in the units.
    How did this "catch" on fire (ignite)?: A better explanation than I could provide is here:
    Adiabatic Compression Explanation

    Short Video - Regulator Fire Causes (Video Short version)
    Full Training Video: 26 Mins (full training video for fire services in the US about 26 mins, this is where the short clip originated)

    Suggested Basic Controls:
    DONT BUY CHEAP OXYGEN REGULATORS - make sure these come with good instructions and are stamped with the standard, not a sticker saying made in China
    Check regulator knob is not screwed in hard, open slightly then adjust once you have a flow
    "Crack" Open pressurised cylinders slowly
    Never install or operate gas cylinders or regulators with greasy or flammable liquids on gloves or hands
    Open these valves from the side, never in front of regulators/gauges
    Wear clean gloves
    Train/re-educate staff

    When purchased this cheaper regulator unit comes with instructions of course, in 20 odd different languages in font 3 or 4 and poorly translated into English.

    There is absolutely no need to have aluminum in these units unless for specific industry based requirements and even then this risk needs to be advised to employees using this type of regulator, the age of the regulator is largely irrelevant.

    But surely these are made to a standard right? Aha, sure except some are made "in accordance" with the standard (stamped made in China), some are made to the standard and this is stamped on the regulator body.

    In fact in the US the FDA and other regulatory bodies have or are trying outlaw these regulators, again I have no doubt there is a need for aluminium to be used in certain circumstances and I dont have the data yet to support similar decisions in NZ.

    Surely these get tested periodically right, like electrical gear and equipment? Nope, there is no current requirement to test these. However prestart checks on each use including the controls given above will considerably reduce the risks and potential harm.

    I acknowledge completely that the frequency of these events are not high, however the potential to put the last links in place is there. I do not have any knowledge of what is used in the medical industry or fire service, but I do know these regulators are commonplace in engineering shops small and large, used by contractors on plant shuts and in high hazard facilities.

    I am hoping Worksafe will provide some statistics on frequency of these events in NZ, if I get these ill post them. On this I have detailed my findings and sent these to Worksafe who are considering these currently.

    Now, as Health and Safety types we have a tendency at times to overreact and insist on controls which can be impractical or even irrelevant, I am not suggesting for a moment that employees be dressed in full face helmets, chain mail suits and flash over gear just to turn on an oxygen bottle.

    But please advise your teams at the least of the story above, check and replace cheap regulators, ensure employees are not winding the oxygen bottle out too fast and operate off to one side. Clean hands and install these units properly.

    I don't want to set off a knee jerk reaction or over reaction, but this incident has surprised many locally in the industry and potentially destroyed this kids career as a fabricator. The boss has just gone through and replaced at great expense all regulators in his shop and is still shaken by this incident and rightly furious that he had no knowledge this could happen.

    On a happy note, the gas bottle supply company needs a significant amount of kudos who have been exemplary in reaction and support and also to my client who has been through the mill on this and supported his employee(s) valiantly through this tough time. I'll be happy to name them when I have consent.

    The purpose of posting here in this forum, is to hopefully get the word out and raise awareness. If you have any similar stories or contributions, please share! If I had my way, flyers would be in every welding gear supply shop nationwide with a quick pre-start guideline as a reminder to all purchasing the gear of installation and basic operation.

    This is one of those occasions where although we couldn't prevent the harm, I am proud to say at least we have the tools to prevent it from happening again, hopefully you will use these tools wisely and practically.

    I promised this young mans father and my client, I would do everything I could to make sure this couldn't happen again or that as the least education around this event was undertaken.

    Cheers Team, please spread the word.

    Safety Logic and
    PJ Safety
  • Lee Bird
    Note the explosion has occured inwards out, the jagged material is aluminium. The hole is where the regulator knob and spring once sat.

    Another incident I have recently heard is where the employee received significant facial injuries where the assembly and explosion struck him
  • Antony Kitchener
    Hi Lee,

    That is quite a horrific accident to happen. I hope that the young man recovers well. I work at a DHB and have been developing guidance around medical gas cylinder safety for this particular reason. Hospitals use large quantities of medical gas cylinders, especially oxygen and other oxidising gases. Combined with the ubiquitous use of ethanol-based hand sanitisers, this creates a need for good guidance and education.

    Did the incident you refer to occur in New Zealand? Is there an investigation report into the incident that is publically available (personal details removed for privacy reasons)? I ask as reports/examples of particular incidents are valuable training tools but the only examples I can find of similar incidents ocuring with medical gas cylinders/diving cylinders are either from the UK, US or Israel. Having a local story would be beneficial when educating and rasiing awareness with staff. Are you aware of any other examples of incidents involving gas cylinders in New Zealand?

    All of our regulators (to the best of my knowledge) have a brass core which should minimise the risk of fires caused by adiabatic compression.

  • Lee Bird
    Hi Anthony

    Thank you for your reply, yes unfortunately this happened in New Zealand other instances have started coming to light after speaking to one of the last experts in regulator/gauge repair in the country.

    I cant release the incident report yet as the gas bottle supply company are undertaking the final part of their forensics on the bottle, to confirm the bottle or contents had no obvious issues or contributing causes. However, when I realised the possible implications my head nearly exploded. After seeing the videos (linked in the post above) my first thought was an ambulance or hospital having this happen or even at a small Doctors Surgery (GP)

    As I go down the rabbit hole on this, any stories I can share will be in this thread and hope as I mentioned we can raise the awareness and deal with it accordingly.


  • MattD2
    Thanks for the detail information Lee. Even when you said it was caused by adiabatic combustion I was still thinking but what was the fuel - shocked me when you said the regulator had aluminium parts.
    Couple of questions that you might have more information on:
    • Do you know what were the specific parts of the regulator that were aluminium?
    • And is there any way to tell (even if you have to break them down to check)?
    • Do you know if the Standard (AS 4267?) specifies brass only construction for Oxygen regulators, or does it allow using aluminium or other reactive metals?
    Thanks again for sharing this.
  • Lee Bird

    Thanks for taking the time to read and for the questions.

    I have to confess I am not an expert on this one and although I can quote standards on Confined space verbatim I am completely new to this topic.

    I promise you though, your questions will be answered in the coming days, I am currently working with the gentleman I mentioned in the original post and with regulator supply companies in my spare time.

    Watch this space
  • MattD2
    Thanks Lee - I miss working with for an employer with a company wide subscription toe the AS Standards!
  • David Brown
    A great article Lee, something really different that I really enjoyed reading. I hope the young apprentice recovers well.
  • E Baxter

    I also work for a hospital and would be really interested to see your guidance material if you are able to share?
    Thanks for raising this issue Lee. Great links as well. Hopefully the apprentice is on the road to recovery
  • Antony Kitchener
    Hi E Baxter. If you flick me an email () I can provide you with the pdfs. I'm sure our capability development team wouldn't mind sharing this guidance with other DHBs. Thanks Antony
  • Cam Smailes
    Excellent information Lee, thanks for sharing.
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