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Posted By Sean Fraser
I am currently researching the issue of chemical first aid with particular focus on acids, in order to implement the best advice to all our First Aiders and to our employees in general.
Although we don't use large quantities in process, we do use acids for sample testing and hence quantities are held in storage and then decanted to be used in small amounts, sometimes on a frequent basis. Irrespective of how far we institute control measures to control the storage and use of chemicals, there remains a risk to users of being exposed to spills (no matter how small) and it is here that we have the problem - the HSDS for Sulphuric acid states that it will have an exothermic reaction to water and hence avoid to contact, yet the same sheet states that in the case of spills onto skin and eyes it should be treated by irrigating with water!
I believe that this advice is misleading and has the potential to cause further unnecessary suffering to any casualty, with the consequence of permanent scarring. Instead of irrigation in the first instance, we are considering training our First Aiders to use absorbant materials to "pat down" the affected areas to remove as much of the chemical as possible BEFORE irrigating the area, thereby reducing any chemical heat damage to the tissues.
Does anyone else have experience or advice to offer on this matter? Any assistance would be greatly appreciated
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Posted By Jane Blunt
I see your predicament and sympathise. It is rather like the instructions for disposing of a spillage of common salt, which includes breathing apparatus and rubber suit. It does not mention throwing it over your shoulder.
You have to delve into the reasons for the entries on the MSDS, and assess the science.
If you poured a cup of water into a Winchester of concentrated sulphuric acid it might well erupt explosively because of the amount of heat liberated, covering everyone in boiling sulphuric acid - nasty! My daughter used to have to dilute down Winchesters of sulphuric acid in her job, and it used to take her all day, because she had to keep cooling the solution in ice at each stage. (btw there is an old adage - always add acid to water, never the other way around)
However, a spill on your skin is different, and you can do exactly the opposite to the above. First there is a lot less acid, and therefore a lot less heat to be produced. If the water is greatly in excess, which it should be, it will quickly dilute down the acid so that subsequently very little additional heat is liberated anyway, and the water itself will cool the mixture because the water is cold.
I would be wary of patting dry with tissues, because you then compound the problem by having dangerous tissues all over the place. If you use the wrong material for mopping up nitric acid, you may finish up with a fire. The casualty will not thank you for delaying treatment by doing this, because acid burns hurt.
Plenty of water, as quickly as possible, as suggested by the First Aid instructions in the MSDS, is my feeling,
Jane
(have degree in chemistry)
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Posted By Sean Fraser
Thanks for the prompt response, Jane.
My initial thoughts were initially that the key word in the MSDS had been "irrigate" - the continuous application and draining of water so that it removes the offending chemical before it has a chance to damage the skin - or to react adversely with the water itself.
In addition to eyewash stations and sinks we have an emergency shower in place which could be used, allowing the "contaminated" water to drain away. I had considered the problem regarding safe handling and disposal of absorbant materials as being an additional danger to not only the casualty but also the First Aider and anyone else in the location at the time - obviously by taking a shower this eliminates any residual risk of harm accordingly.
However, the issue was raised recently in discussion with our laboratory department when an example incident was reported where a young woman had been sprayed with sulphuric acid up her arm, across her chest (which was exposed by the wearing of a v-neck top), neck and face (bearing in mind she had been wearing a lab coat). As a First Aider herself, she took immediate action and instead of washing the chemical off she used paper towels first, then washed. Apparently, having presented hereself to the hospital A&E department afterwards and reporting her actions, she was told she "had done the right thing" and that not many people would have reacted "correctly". You can see why I am now uncertain if the usual advice is actually the best practice to employ.
It is interesting to explore these issues from time to time - established thinking does sometimes have a habit of being changed! I'll continue looking into the matter and will report back my findings. Thank you again for your contribution.
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Posted By John Webster
Sean
I have to agree with Jane. Lots of water and quickly for mineral acid on the skin.
The tissue damage from concentrated sulphuric and nitric acids is horrendous - whilst the acid is still in its concentrated state. One of the first things the acid tries to do is react with water from the tissues, reducing organic matter to a carbon char. You have to give it an alternative source of water before it destroys the protective skin.
The only time soaking up with paper towels is of benefit is whilst running to the water source (and watch they don't catch fire!).
And don't worry too much about containment of the washings - this is of secondary importance and only necessary if the original quantity of acid is significant. 10ml on the skin will be completely neutralised by mixing with the natural alkalinity of 10 minutes worth of typical tap water.
John
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Posted By Ken Taylor
The Brunel University CLEAPSS School Science guidance is:
If splashed in eye: Flood the eye with gently running tap water for 10 minutes ..
If spilt on skin or clothes: Remove contaminated clothing and quickly wipe as much liquid as possible off the skin with a dry cloth before drenching the area with a large excess of water ..
Personally I suspect that the circumstances of a particular incident will tend to help determine the first-aid response. If a shower was immediately available this would seem the appropriate option.
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Posted By Jane Blunt
I have had further thoughts. If I were a person at your workplace, splashed with acid and treated as you propose, unless you can prove, using research and real evidence, that deliberately delaying the application of water in order to dab off the excess acid results in LESS tissue damage, then I would sue you, citing your failure to follow the manufacturer's instructions. The endorsement of A&E unless they can produce some research evidence to back it up would be of little help, and I, personally, remain totally unconvinced without that evidence.
I also thought about the people working there. They should ALL know how to deal with a spill, and by the time the first aider has been located and has attended, then the initial first aid treatment should already have been done.
I don't think we ever established the concentration of the acid. This has a great bearing on the kind of damage it can do and the exothermic reaction that results from its dilution.
Jane
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Posted By Sean Fraser
Taking account of everything that has been said to date then the obvious way forward is to ensure that all staff have been instructed to use the emergency shower if they come into direct contact with acid, unless the affected area is small enough to be dealt with under the tap.
It was interesting to read about the The Brunel University CLEAPSS School Science guidance - whether that could be cited as an authoritative reference in court while I am being sued by Jane (!) is open to doubt. The intention is always to treat the casualty as rapidly as possible, without putting yourself or others into danger or causing further harm to the patient. If the drenching of the casualty will immediately offset the damaging effects of the chemical contamination then that is the primary response - the dry materials instruction could confuse the attending First Aider in what is already an obviously stressful situation and could unnecessarily delay treatment through indecision. A short and concise instruction will be given to all staff accordingly, so they are aware of the correct action and they are not, as Jane warned, waiting for a First Aider to attend in order to take action. This will now be re-inforced by placing a permanent sign in the lab.
Staff are currently instructed to wash spills off, as per the standard response. What I was investigating here was whether or not that was the best advice to give - it would now appear to have been bourne out.
Thank you all for your advice.
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Posted By David Johnson
I think if Sean checks with the A&E department he will find their words to the casualty were more about reassurance than confirming best practice. I find the medical profession often make these kinds of informal comment maybe for the best of reasons but they can cause confusion. I think A&E would officially advise on the line of Janes response.
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Posted By Keith Higgs
We always wash off with copious amounts of water immediately (not that we have many incidents). However, there is a product on the market which is supposed to work better than water for acids called Diphoterine. A link to information is:
http://www.cornelius.co.uk/cep/diphoterine.htm. I have no experience with this product although I was tempted to purchase it once. It has a shelf life of 2 years now I believe but at the time it was a year.
Might be worth a try.
Keith
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Posted By Geoff Burt
Interesting thread.
My first port of call with this type of query is to contact the company who issue the MSDS to ask their advice - I just wondered why this has not been considered?
Geoff
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Posted By Graham Bullough
"Copious amounts of water" should be the key first aid phrase for acid on the skin. A good illustration is provided by a serious accident to an electrician walking through the plating department of a large engineering factory about 1985. He stepped on what he thought was a large piece of cardboard discarded on the floor. However, readers will be amazed to learn that it was actually placed as a cover for a tank of nitric acid which was wholly recessed in the floor and used to de-plate inadequately plated products. He plunged into the vat and was immersed to his waist in the acid.
He promptly went to use the emergency shower in the plating department, but found that its flow of water was insufficient to rinse away the acid and alleviate the burns. He wanted to get in one of the water rinse tanks of the plating process. However, as none of the tanks were labelled he couldn't take the risk of exacerbating his condition by inadvertently getting into a chemical tank. Another employee then promptly used a fire hose to continuously deluge him with water until an ambulance arrived to take him to hospital where he remained for weeks or even months afterwards. The accident was totally avoidable and the firm had no credible explanation for never having guarded the recessed tank of nitric acid. It was rightly prosecuted by HSE and received a hefty fine.
Among the various lessons presented by this incident is the benefit of having copious amounts of water immediately available in relation to the amount of acid and size of affected skin area. It was thought that the delay in effectively diluting and removing the nitric acid resulted in greater injury than would have been the case if the electrician had been able to get into one of the large water rinse baths. If this had been the case he would probably have suffered less damage to his hands which occurred mainly from using them to try and remove acid soaked trousers, etc. while under the emergency shower.
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Posted By Keith Archer.
As mentioned by Geoff the MSDS is the first point of information to find out how to provide first aid treatment (amongst other items of information) and should have been consulted as part of the COSHH risk assessment before any substance is used. We should always follow the first aid instructions given in the MSDS as this is the information provided by the supplier as the most appropriate method of treatment. Just to give another reason for the need to consult MSDS, chemicals react differently and at different rates upon the body and indeed some chemicals may react even further if exposed to water.
Keith
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Posted By John Webster
Graham's response also prompts another important point, to regularly check and test emergency showers, eye drenches etc.
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Posted By Laurie
I can assure you this is quite serious - I have worked in areas in the past where, in the field, the proper Immediate Action for chemical contamination of a casualty was to urinate on him!
It works, and I would rather take my chance with that than have somebody faffing around with tissues etc!
Laurie
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