Why mercury is forbidden aboard airplanes

http://www.popsci.com/scitech/article/2004-09/amazing-rusting-aluminum

by rogercosseboom • 17 years ago

94 41 17 years ago

popsci.com

schtono• 17 years ago

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

framiere• 17 years ago

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

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

wallflower• 17 years ago

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.

biohacker42• 17 years ago

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.

cdr• 17 years ago

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

jcl• 17 years ago

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...)

bd• 17 years ago

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)

electromagnetic3• 17 years ago

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.

Tangurena• 17 years ago

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).

timbowen• 17 years ago

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.

raghus• 17 years ago

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.

electromagnetic3• 17 years ago

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.

spoiledtechie• 17 years ago

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

Jees.

pbnaidu• 17 years ago

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

jodrellblank2• 17 years ago

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}?)

tlb• 17 years ago

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.

jodrellblank2• 17 years ago

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.

Shaitan_Apistos• 17 years ago

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

mattmaroon2• 17 years ago

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.

imp• 17 years ago

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

electromagnetic3• 17 years ago

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.

Rod4• 17 years ago

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?

blasdel• 17 years ago

Did you ever notice that aircraft are painted?

noonespecial2• 17 years ago

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?

mattmaroon2• 17 years ago

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

twopoint718• 17 years ago

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

tlrobinson• 17 years ago

Or, you know, because it's toxic?

tjmc• 17 years ago

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.

Why mercury is forbidden aboard airplanes

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