Why mercury is forbidden aboard airplanes | Hacker News Reader

Why mercury is forbidden aboard airplanes

popsci.com

Guess I'd better leave my fillings behind next time I fly.

(Side: Why is it that so many people go "ooh it's neurotoxic!" and when I mention fillings they say "oh but that's different, it's a stable form of mercury mixed with {arsenic, radium, cyanide, other weird thing I don't really want embedded in my flesh}?)

Well, it's true -- mercury in an amalgam (normally with silver & tin) doesn't leach out. Most of the heavy metals that are dangerous by themselves can by alloyed or chelated to make them biologically safe.

This video from the International Academy of Oral Medicine and Toxicology - http://iaomt.org/videos/ - shows mercury vapour being released from a filling under such ordinary situations as drinking a hot drink, chewing, etc.

This episode of Skeptoid - http://skeptoid.com/episodes/4036 - discusses this very video and concludes that what we're actually seeing in the video is water vapour (since mercury vapour is much heavier than air, why is it rising in the video?).

We also should be careful with Macbook Pros especially the unibody ones...

Chemistry is fascinating. I'm really not too worried about mercury being the next terrorist secret weapon. It doesn't seem flasy enough to inspire terror, maybe just a creeping unease.

So if you're Al Queda, the play here seems obvious. Get as many sleeper agents in the U.S. as possible (which I'm sure they're constantly working on) and each day send a couple on a plane armed with an old thermometer. How many could you take down before people realized what was going on? And after they did, how much damage would it do to the economy when nobody flew anymore?

I sure hope I'm missing some secret reason why this wouldn't work well.

I wonder if the mercury in the thermometer would set off the metal detector. It might be hard to get it past security.

Good wonderment, but I believe it wouldn't. I've broke one open before when I was about 15, I knew at the time mercury was dangerous so I opened the window and avoided direct contact completely (rubber gloves) and if you ever wondered, mercury does absorb into paper towels. The total amount was smaller than a penny, and I've forgotten to take my belt off before, left my phone in my pocket and even a few dollars in change one time, so I don't exactly see how it could set it off... or the airports I fly from are cheaping out on the security to save money, using sort of like a placebo effect like the fake cameras you can buy for $20 to 'protect' your home.

Wouldn't it be easier to create a modified water-gun (a sort of super soaker on steroids, so to say) and splash airplanes at the airport with mercury from a few hundred yards away? Sounds crazy, I know, but it would be a lot cheaper and more discreet than using stinger missiles, right?

Did you ever notice that aircraft are painted?

Couldn't one assume a priori that not all paints are mercury-resistant? If Aluminium is corroded by mercury, would it be unreasonable to conjecture that some paints are too?

From what I know, it's possible, but it's not the kind of thing that I would assume a priori. I'd actually go and check to see if it worked.

I honestly do hope that paint is mercury-resistant. Otherwise, any terrorist-wannabe with a paintball gun and balls filled with mercury instead of ink would be able to cause a LOT of damage.

In the article they mention that it would be dangerous to bring mercury to the aircraft's cabin. Well, I have never seen an aircraft cabin where the aluminium fuselage was exposed. Thus, I thought that mercury would corrode all the way to the fuselage. From that to inferring that it would corrode paint as well would not be unreasonable, right?

Otherwise, any terrorist-wannabe with a paintball gun and balls filled with mercury instead of ink would be able to cause a LOT of damage.

I think that it would be easier and cheaper to simply fire actual guns at the plane. A hit on a wing will bring down the plane quicker than mercury and hits will be easier.

From that to inferring that it would corrode paint as well would not be unreasonable, right?

It wouldn't, but I think that the article exaggerated the danger a bit. I don't think that the mercury from a single broken thermometer would eat through the floor and reach the fuselage. At least, I've never heard of it happening.

You are totally right and I am a fool for having allowed super exaggerated articles like this one to fire that region in my brain dedicated solely to imagining cheesy James Bond-like movie scripts ;-)

The fuselage isn't exposed from the cabin, but what about the cargo compartment? If enough mercury paste leaked out of your suitcase, the plane could be in trouble. I'm thinking if you had enough mercury to damage the plane it would show up on the X-Ray though.

The mercury has to more or less be a special paste and be smeared in the right area. The surface tension of ordinary liquid mercury seems too high to get the alu "wet" otherwise.

I umm.. ehem.. went and maybe umm tired it a little bit after seeing this because it sounded so darn cool. The liquid mercury I've culled from old thermostats had no discernible effect.

Edit: I tried it on a piece of aluminum angle bar. I even tried filing it a little to rough it up. Nothing. Anyone else had any success?

That article most definitely should have come with a "dont try this at home kids" at the end.

Even better, a "but if you really want to, here's the best way" just after that.

We're hackers. We always try this at home.

<irony>I'm glad we have a 100ml limit on liquids to be carried on airplanes</irony>

You would do a remake of "snake on a plane" with your 100ml ?

http://www.break.com/index/burning-mercury-experiment.html

This is really scary stuff (and I was hoping that it would never make it on HN). I heard from an aeronautical engineer once that if one drop of mercury somehow gets let loose in an airplane that the whole plane needs to be basically taken apart (and possibly scrapped).

Mercury by itself is very toxic. There was a custodian who broke a thermometer in our office building once. That would have been ok - had she not spread it everwhere by playing with it. And, speaking from experience, as someone who broke a thermometer as a kid in his room and was mesmerized by the liquid, I can't blame them. Whole building had to be detox'd - almost spaceman suit E.T. style.

This is really scary stuff (and I was hoping that it would never make it on HN) I saw this on reddit today and a few of the better comments debunked the scare mongering hype: http://www.reddit.com/r/science/comments/85clw/why_mercury_i...

And yet here we are with popsci near the top of HN. I blame Jeff Atwood.

PopSci from 2004, no less. Did Atwood finally break HN?

Atwood is starting to become Emmanuel Goldstein around here.

Am I in time for today's Two Minute Hate?

Note that the comment "debunking" the article is by the author of the article itself (or so he claims). The debunking seems to consist of repeating what is in the article: the FAA doesn't allow large amounts of mercury, as is present in a professional barometer.

The scariness of the article seems to reside mostly in the comments here and choice of headline. (although the picture of the dissolving I-beam isn't particularly reassuring...)

Well the comment biohacker24 linked to wasn't really debunking it, but it was by the popsci author (supposedly).

Both of these comments (in the same thread) do debunk it:

http://www.reddit.com/r/science/comments/85clw/why_mercury_i...

Wow. That was my first Reddit experience in a long time - I appreciate the links, because I wouldn't have come close to trawling through the conversational inanities to find the nuggets of perception buried in a shit-storm of self-flagellation.

Dear HN - I love youse guys.

Yeah the whole thread of Sherlock Holmes quotes totally threw me... I knew reddit was bad... but that bad? Wow.

Whole building detoxification because of a single broken thermometer seems like overkill (unless it was some unusually big one).

It's important to clean it properly (good ventilation, don't spread it around, don't vacuum clean), but unless you do something really stupid (that would get significant amount vaporized and inhaled), it should be ok.

Perhaps the most important thing to remember if you break a household thermometer is do not panic. The amount of mercury contained in an oral thermometer is small and does not present an immediate threat to human health.

http://www.atsdr.cdc.gov/toxprofiles/phs46.html (CDC Public Health Statement for Mercury)

I broke one by accident when I was around 15, the total amount is about the size of a penny because the liquid is heavy and doesn't form a nice 'bubble' like water does.

IIRC I used a paper towel (whilst wearing rubber gloves, with the windows all open) to absorb the mercury and slid it into a plastic bottle and bagged it like 10 times before I went outside to make sure I wasn't exposed too long.

From my understanding they recommend all the precautions, not because like one drop will kill you, but because "it's better safe than sorry". You have an entire lifetime, just like you shouldn't be exposed to a huge dose of radiation, you shouldn't expose yourself to a huge dose of mercury, because fish contain mercury (and my lack of eating fish has likely balanced out any mercury I was actually ever exposed to) and if you eat tons of fish, sucking on broken thermometers and breaking florescent bulbs might just get enough mercury into you to make you nuts... although if you're purposefully exposing yourself to raw mercury to begin with I believe it's probably a moot point.

One dorm at a university (fau is commonly called "find another university") I went to had to be shut down in 1994 for decontamination, as some students stole mercury from one of the chemistry labs and played with it. I can't find how much it was on the web, but I seem to remember it being about 1 quart of mercury (about 25 pounds).

This effect can be beneficial. Swap the mercury for gallium and you get a neat way of producing hydrogen on demand: http://cleantech.com/news/1205/gallium-and-aluminum-tigers-i...

Too heavy for aviation but potentially useful for fuel cell vehicles.

This makes me think of mercury as the Ice-9 of aluminum. Does anyone have videos of this reaction?

So, those old-style thermometers with mercury - even that much mercury could shred an airplane?

I know knowledge is power and all that, but I almost wish I hadn't found out about this.

Honestly with the mere fact that for a flight to count as a flight the pressure differential has to exceed 2 PSI. Any metal exposed to mercury (by a passenger) is likely going to weaken in a radial fashion from point of contact, which means in a pressurized cabin, it shouldn't take long before the air pressure ruptures the leak and the plane would be forced to land due to depressuring.

I doubt this would do serious harm to a plane before landing. I doubt if this would even matter in an unpressurized cargo hold because I was always told it evaporated quite quickly at low pressures.

"The few-micron-thick layer of aluminum oxide is the only thing holding an airplane together."

Jees.

Or, you know, because it's toxic?

Clicking on the link to the article crashes the browser on my tmobile g1 for some reason, anyone else?

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