Hydrofluoric acid is a colorless liquid that mixes readily in other fluids. It’s highly corrosive and is classified as an acute poison that immediately begins to degrade tissue on contact.
If you’re a fan of the Breaking Bad TV series, you might remember that this was the acid that Jess Pinkman used to dissolve a body in his bathtub, the tub that eventually was eroded by this acid and came crashing through the ceiling.
Ironically, when hydrofluoric acid comes into contact with skin, it initially causes painless burns. Several hours after exposure, however—even after washing the skin—deep, irreversible and painful damage can result and tissue death follows shortly after.
But the damage doesn’t stop at the skin’s surface. After contact, the acid interrupts the body’s calcium metabolism and causes systemic toxicity. As the body’s calcium balance is further disturbed, systemic calcium metabolism is halted. This can lead to cardiac arrest and death. And it doesn’t take much to create this cascading lethal effect. As little as 25 square inches (a 5”x5” area) of affected skin can lead to death.
For example, a drink laden with hydrofluoric acid spilled on someone’s clothing could be
considered accidental and easily forgotten. But, over a period of a few hours, the person’s skin would begin to dissolve, calcium metabolism would be interrupted and the person could die from a heart attack.
It’s easy to see how this acid could be an intriguing method of killing off a character in your novel and still not have it link back to the murderer since visible damage may not appear until hours after exposure.
As one might expect, the degree of tissue damage and the resulting lethal effects of this acid depend on the amount, the route, and length of time of exposure.
For instance, if this acid were added to someone’s eye drops or a nasal spray, the systemic damage would be accelerated due to the greater absorption rate of the acid into ocular tissue and mucous membranes.
If used as a nasal spray, lung tissue damage is assured. Lung tissue swelling and fluid accumulation could cause an irreversible pulmonary edema and the victim would essentially drown in his or her own fluids—thereby allowing a writer to create a rather dramatic murder scene.
And swallowing only a small amount of highly concentrated hydrofluoric acid will cause major organ damage and, more often than not, result in a painful death.
Furthermore, if the person suspects that he or she has been poisoned and vomiting is 
induced, then the tissue damage is enhanced throughout the upper GI tract. This results in even greater absorption of the chemical into mucosal tissue and a more effective shutdown of systemic calcium metabolism. In short, the end result of induced vomiting is a more rapid advancement to cardiac arrest.
One of the reasons this poison would make such a great murder weapon is that hydrofluoric acid is readily available in auto parts stores. It’s one of the main ingredients in aluminum wheel cleaners.
I have not yet had the chance to use this interesting chemical as a death tool in a murder scene, but the possibilities are intriguing and as numerous as the routes of administration for this versatile poison.
Thoughts? Comments? I’d love to hear them!
Prescription For Murder 
Jim,
There is no doubt that hydrofluoric acid is dangerous stuff and can be used as an effective fictional murder weapon, but it is also true that TV shows are not the best place to learn science. MythBusters (http://www.today.com/entertainment/mythbusters-proves-breaking-bads-walt-needs-some-more-schooling-6C10904583) proved that it is not an effective way to actually dispose of a body, nor will it cause a bath tub to come crashing through the ceiling. Actually, that is better for the murderer — maybe more time until the results of her crime are discovered.
Walt
Yes, that might be good news for the murderer if the crime is not discovered when a bath tub comes crashing thru the ceiling – you have to love the drama of television or a good fiction story! Thanks for your comments.
Okay, this is going to stick with me every time I use eye drops or nasal spray. How do people who use this stuff for cleaning wheels keep themselves safe. And are there other uses?
LOL – Yes, Jinx, this stuff is dangerous to handle. People handle this carefully, and with gloves. Other uses for hydrofluoric acid include making freon, making Teflon products, for etching glass, and it’s used in a bunch of other industrial manufacturing processes. It’s actually amazing how easily accessible this product is to someone who knows where to look for it. Thanks for your comments. All the best to you!
Breaking Bad also suppossedly used hydrofloric acid to disintegrate a body in a plastic barrel. Then they just poured out the fluid somewhere. Would that work? How long would it take to turn a body to liquid? Ugh! This is so disgusting. That’s why it would work perfectly in a story. Thanks Jim, you sick puppy.
LOL, Mary! I can picture you rubbing your hands together and thinking up a good plot. 🙂
Yes, hydrofluoric acid would work well in a plastic barrel (it would eat through a metal barrel) and it would take maybe a few days to a week to dissolve flesh and bone. Have anyone in mind? 🙂
Take care and thanks for commenting – All the best to you!
Hi James
Great article. Informative as always. Thanks for sharing your knowledge. I’ve missed a couple of your posts, I think — new software upgrade did violence to my contact lists, consigning some to internet pergatory (the Junk folder!). Thought you were taking a hiatus, but finally tracked you down! Enjoy your articles.
(Another) James
I was wondering where you went – I missed your comments!! Glad you’re still among the group of readers and thanks for your comments. All the best!
Incredible story there. Whaat happened after? Thanks!
Oh, lots – you’ll have to see the series to find out! 🙂
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what will be the effect if concentrated hydrochloric acid is consumed per oral?how much will prove fatal enough to kill some one?
An interesting question! Stomach contents are acidic because of its hydrochloric acid content (usually between pH 1.5 and 3.5) with each degree of pH being 10 times more acidic than the previous number. For instance, a pH of 2 is 10 times more acidic than a pH of 3. There is no 100% pure hydrochloric acid (with a pH of 0) but somewhere around 40% is highly acidic and a very small amount could prove fatal if swallowed. The predominant effect would be severe burning of the mouth and throat and cause severe swelling of the throat, which will interfere with breathing.
I was wondering would it then be possible to ingest an organic (or even inorganic if prepared quickly and want it to dissolve in the stomach) capsule to avoid burning of the throat and mouth, thereby leading to less traceable symptoms?
More than likely, the corrosive/highly acidic content of the capsule would dissolve the capsule also. And if you used a capsule that did not dissolve in acid, then it would not dissolve in the stomach acid (Hydrochloric Acid-rich) juices either. So I don’t think that’s a good possibility.
I’m writing a story where victims are dropping dead from heart attacks and was wondering how many ways there are to do this where the method used is undetectable. I saw your blog talking about potassium chloride and thought I might use that as the method but I’m afraid there may be other means of doing the same thing that some reader will come up with. If you have any suggestions I would be very grateful!
Thanks for a wonderful and informative blog; it’s such a great resource!
Thanks, Wendy, for your kind words. Many poisons end up causing cardiac arrest, but the remaining poison trace is always a giveaway. Potassium Chloride is a good choice since it causes complete heart failure, and a heart attack often increases the blood’s potassium level. Other suggestions out there for Wendy?
Thanks so much, James! I can now keep writing, sound in the knowledge that I’m unlikely to be assaulted by a roving band of ‘what ifs’ 😀
I am no expert so feel free to correct me. But I’ve also wondered if one could use a concoction consisting of many small doses making it all the more difficult to trace as there would be no one agent in a great enough concentration to be a lethal dose? Just thinking out loud would be great to hear your feedback on this.
I don’t think small doses of a multiple acids would work – the sum of the acidity of multiple types of acid would leave signature trace also. I’m sure you could google “synergistic effects” of various chemicals and maybe come up with a lethal concoction for you murder scene.