Posted By Brando Has anyone any experience of battery acid burns? If diluted battery acid from a fork lift got on your skin how long would it take to burn the skin ( presuming you didn't wash it straight off )? I thought the diltuion rate was so low that a burn would be very very unlikely? ( not talking eyes here - just skin ). Thoughts? Brando

Posted By Brando Ian Thanks - take and understand your point on dilution rates. I have no idea what the standard rate of dilution is on a fork lift battery but I am assuming it is similar to a car battery? How long before a burn if the diltuion rate was correct for the battery - which I am presuming is pretty dilute? Brando

Posted By Ian Futcher Brando, please don't assume it's dilute. 50% H2SO4 in water looks like and slops about like a 0.5% mixture. Sticking in some pH indicator paper will not help determine the concentration, for both the solutions described above will show a pH of approx 1. 1-2% solutions could cause burns if held against the skin for 10-15 minutes, and could have no visible effect on the fabric on which it was absorbed. I've just googled something about battery acid and it suggests the concentration may be around 70%. hmmm.. thinks: I might need to review my risk assessments... Ian Ian

Posted By Merv Newman "neat" sulphuric acid is 96% H2So4. For battery use this is usually diluted to 50%. From memory, as a chemical student, you have about five minutes to wash it from your skin before you start to get burning and subsequent scarring. Nitric is a lot faster, hydrocloric is slower. Hey, nostalgia. But you don't get anywhere near any of them without the three Ps : Prevention, Protection, Prophylaxis. What are safety showers at charging stations for anyway ? I think my left (the kicking one) foot is starting to throb. Brando, sorry if I have offended you. But please remember that the acid in your batteries contains the equivalent energy to drive the truck for an hour or so. Yes, I know I'm being simplistic so, if you want an equivalent, just try dropping a car battery on to your bare toes from a height of 1 meter. Will it hurt ? And I am not going to calculate foot-pounds nor ergs per fortnight. Merv

Posted By Brando Merv Not sure why you think you may have offended me? Always open to comments. I was just rather confused this morning when someone started talking about batteries and my brain seemed to have a gap when it came to some basic info ( hence my questions )!! Brando

Posted By Melanie Fellows Crikey Merv, you are amazing! Are you available for after dinner speeches?? Mel

Posted By Dave Merchant In case anyone is reading this thread and taking notes for COSHH, lead-acid batteries DO NOT USE 50% DILUTION. The initial settled concentration after plate stabilisation and first charge is 33% like I said earlier. As the battery discharges in use, the effective concentration of H2SO4 falls, and a fully-dead cell can be under 1% (but don't assume it and stick your finger in). Some of the couch chemists who've replied should read their textbooks. I suggest:- Battery Reference Book, 3rd ed. Thomas Roy Crompton, ISBN 075064625X

Posted By Ali Of course the acid is just one half of the equation - the other half is the skin itself. Skin is not homogenous neither is it the same for every person. It varies with age, race, gender and what might afford a barrier in one person may be completely breached in another. Some people are literally "thick skinned" and the extent to which the skin is affected by chemicals depends therefore not just on the chemical, but also on the skin type and to a smaller extent on any skin barriers that may be present.

Posted By Chris Packham Just to add to what Ali has posted: Skin thickness actually varies very little. in fact, the outer layer of the skin, the epidermis, which is the barrier layer over most of the body, is only about 0.1mm thick. However, Ali is correct in that the skin is unique to each individual and thus may react differently to something such as dilute acid. More importantly is the fact that irritant contact dermatitis (as opposed to a skin burn) is almost always chronic and multifactorial, i.e. develops over time as a result of repeated exposures to many different irritants (including water!). This damage is sub-clinical, i.e. cannot be felt or seen. Only when the skin's ability to resist (the "threshold") is breached will you see the dermatitis. So the exposure to the acid, whilst it may not appear to have done any damage, may increase the subclinical damage to the extent that exposure to some other irritant will result in dermatitis. As a final point I quote the words of a leading US dermatologist, Prof. H. I. Maibach: "There is probably no such thing as a non-irritant substance. Given sufficient exposure almost any substance will cause irritant contact dermatitis." So even if your exposure doesn't seem to cause any immediate effect, do not be deceived. Chris

Posted By Merv Newman Thanks to those who have given more technical replies than mine (above) I was just trying to be "man-in-the-street ish" with a simple warning to Brando that acid contact ain't that simple. Which you have confirmed. On the "smell" comments, sulfuric acid doesn't have much of a smell. Rather sweetish as I remember. Not enough to give any kind of warning sign. Nothing like Hydrochloric, Nitric or even (especially) Ammonia. And how many of your FLT battery charging stations have that funny white encrustation on the floor ? Brando, yes, we do do "after-dinner" speeches. But it takes a lot of dinner, plus a few "afters" Merv

Posted By FAH It's good to see all the really useful stuff coming out - thanks Chris & Merv in particular as it has given my brain cells a jog as well. Strange Brando, but I didn't see any backgound as to why the question was originally asked. Anyway - just to horrify all you good people [I'm not including you Merv]; in my previous life it was entirely normal to see senior officers sniffing, testing viscosity with fingers, & even tip of tongue tasting all manner of strange substances that someone else had spilt! Us mere mortals in SCBA & Hazmat kit wouldn't do that, 'cos we had a far better perception of our own fallibility & mortality. Them wuz the daze!! [or were they?] Frank Hallett

Posted By Robert K Lewis All this reminds me of the events when the 600 year old lead coffin of Little St Hugh of Lincoln Cathedral fame was opened. The archeologist concerned tasted the contents and remarked that they had a salty taste.:-( With regard to suphuric acid the analar reagent makes a very passable citiric acid substitute at 0.1M concentration. Serious damage to eyes happens even at this level of dilution and by the time you reach around 1M, about 4-5%, you have a recipe for damage to skin, thick or thin. Between these two figures it really does depend on the length of exposure. Bob