where a guy goes to the ER with what he considers to be a relatively minor acid burn. After some research the doctors tell him that in fact he’s got less than a day to live because the Hydroflouric acid will catalyze a crystal reaction within his body that utlmately kills him (if I remember correctly it may have been hypo or hyper kalemia that did him in). There was no effective treatment and the guy got progressively worse and died. Is this just Hollywood fantasy? Can what seems like a relatively small acid burn leave you feeling okay initially, but then dead just a day later? This is especially fascinating given that HF is a weak acid!
Yes. Hydrogen flouride is deadly to humans in any amount. Thats why the CIA coats its tinfoil beanies in it.
I hope this is helpfull.
Purely anecdotal, I know, but a friend of mine works with industrial chemicals; he told me basically the same thing. It can be deadly because the symptoms can take a while to appear, and by then it can be too late.
Now for a cite:
And:
So yes, its some dangerous stuff, even in small concentrations.
I used to work with it and it was one of the very few chemicals which ever gave me the heebie jeebies. Anyone who uses it should know to have a tube of the antidote gel within easy reach. The antidote is only useful, though, if you apply it straight away as it causes the fluoride to precipitate out before it gets into your skin and attacks the muscles, bones and connective tissue.
the stuff. What were they thinking? Lab, was crazy and it was not uncommon to have spills, ect. Seems like this should be reserved for highly controlled environments.
here are some case studies from http://ehs.unc.edu/pdf/HydrofluoricAcid.pdf (pdf file). Fluoride is probably as toxic as cyanide, though evidence is mixed
A dermal exposure to 70 percent hydrofluoric acid over a 2.5 percent total body surface area resulted in death. The serum calcium level was 2.2 milligrams/deciliter.
������ An adult patient who developed 25 percent total body surface area second degree burns after exposure to a 70 percent hydrofluoric acid preparation died in cardiac arrest. Ionized serum calcium level was 1.7 milligrams per deciliter (normal: 4 to 4.8) immediately premortem.
������ Two workers died following a splash exposure of 70 percent hydrofluoric acid to the face, chest, arms and legs. Both workers were promptly removed from site of exposure. Clothing was removed and burns were initially treated at the workplace with a cold shower and alcohol was applied to burn areas. Suitable protective clothing was not worn at the workplace.
������ A woman died from severe chemical burns of the skin and lungs, with intense pulmonary hemorrhagic edema after having acid thrown onto her face during an attack.
������ A patient with HF burns involving 8 percent of his body died from intractable cardiac arrhythmia secondary to the depletion of ionized calcium.
Hmmmm… are you sure you were using hydrofluoric acid?
was a raving maniac (which I may be, but that is a different point entirely). It was only on a couple of occasions, and was accompanied by stern warning, but still why take the chance?
No kidding! From http://www.ehs.neu.edu/hf.htm a list of precautions:
Now that sounds like something I wouldn’t be too eager to play around with. If people who have to work with it get the “heebie-jeebies” I can’t imagine having to do school lab experiments with it. Give me a C and I’ll write a report on it. Then again, i’m a wimp (with a fear of deadly chemical burns). YMMV
Hydrochloric acid is quite commonly used in college chem lab experiments. Hydrofluoric acid is a completely different animal - it is most certainly NOT a weak acid! I’d be willing to bet everything I own that there is no way you used HF in a regular chem lab because of the dangers involved. I’m not joking. I occasionally use a 48-51% HF solution to etch certain kinds of rock chips to prepare them for viewing under a scanning electron microscope (SEM), and frankly the whole process makes me sweat a little until it’s finished. Proper use of HF requires an appropriate fume hood (one capable of handling the corrosive fumes that HF generates), teflon beakers and forceps (because HF will eat through glass), safety goggles and special chemical-resistant gloves and lab clothing.
A couple of items that will help illustrate the danger more clearly (note: PDF files):
Material Safety Data Sheet for 49% Hydrofluoric Acid
Recommended Medical Treatment for Hydrofluoric Acid Exposure
Bottom line is - yes, the scenario described in ER is quite possible.
Exactly sunfish, thats what I was thinking… weak acid, and hydrochloric sounds a lot like hydrofluoric. I don’t think they’d let college kids loose with hydrofluoric acid…
I can’t vouch for the strength of the acid we used (I think it was rather dilute). Also, I am confident that HF was one of the weak acids that we had to memorize. Keep in mind that acid strength is defined by it’s disassociation constant rather than it’s effects upon the human body. With HF the real danger isn’t the superficial chemical burns, but rather the systemic, subsequent reactions within the body that occur. Indeed, the “weakness” of HF may contribute to its lethality in that someone may not realize the seriousness of the injury and seek help in time (it may also play a part in it’s ability to penetrate tissue, but now I speculating).
As I posted in my first reply, the free hydrogen ions cause the CORROSIVE or “superficial” burns, the chemical burn is caused by flouride ions… so yes, you’re right… a low concentration does cause larger problem for that reason, the physical or superficial symptoms take longer to occur, while the chemical burn has had more time to chain-react.
For what it’s worth, I know that my high school Chemistry teacher worked with HF occasionally in lab, but that was doctorate level stuff and she described conditions consistent with what robotic_panda describes.
Yes, HF is a weak acid w/r/t the number of hydronium ions (H[sub]3[/sub]O[sup]+[/sup]) generated when it’s dissolved into water. In terms of corrosive effects it’s not. Remember, Roland, that there may be plenty of people reading this post who don’t automatically know what the term “weak acid” means in a chemistry context, so it’s good to explain such terms a little when you use them.
Dilute solution or not, I’m curious as to what undergrad class had you using HF in a lab, and what the experiment was. If anything, working with a very dilute solution is a very poor idea with relatively inexperienced students, as “dilute” tends to be translated internally as “not so dangerous,” a really bad thing with HF in particular since the signs of exposure are delayed that much further with a more dilute solution. You’re a nursing student, yes? I’m hard-pressed to think why you would be working with an inorganic acid of that caliber, but I’m willing to learn.
HF burns are not inevitably fatal. A guy I know who works with it regularly (and knows what he’s doing) managed to get some on him, and he’s still alive and kicking. I note that he immediately took action and got immediate help. It still required the removal of large chunks of flesh, though. Not trivial stuff to fool around with.
I can’t believe that they would use this stuff for an undergraduate lab, or even a graduate lab. Most experiments can be done with some non-exotic acid (You can’t even keep HF in glass bottles – it eats through the sides. The used to have to keep it in wax-lined containers. Nowadays they keep it in plastic). If you want to etch glass, you can use ammonium bifluorite. What the hell would they have you using HF for, anyway?
Hydrofluoric doesn’t always come in lethal concentrations. You can, for example, buy it as a cream for etching glass. I used to have a bottle of it around somewhere. It’s still pretty nasty stuff and you need gloves, long-sleeved shirt, and a face shield to use it safely. But it’s certainly not unreasonable to think that it might be used in a chemistry lab safely.
Again, if its for school, which i’m paying for anyway, i’ll finagle (no pun intended) a C for a report on the caustic properties… gladly.
When I took general chemistry as an undergrad, it was not uncommon for people to get drops of stuff on themselves or on their clothes. I burned a hole in my sweater once using HCl, even though I thought I was being very careful. Other jokers liked to do things like try to see whether they could remove their fingerprints. :rolleyes: Safety procedures may well have been tightened since I took those classes (early 90s), but the only thing we had then was safety goggles. As noted above, HF requires some heavy-duty protective measures.
(Corrected link for HF material safety data sheet in PDF)
The first couple of times I used HF, I was personally supervised every step of the way by a senior lab person, and this was AFTER taking the mandatory lab safety class required by my graduate institution. I’m having a really hard time imagining what basic chemistry principles could be illustrated only with the use of HF, as opposed to something less hazardous, especially given the propensity for undergrads to do something stupid or careless (and the level of liability assumed by the school!).