
Why mercury is forbidden aboard airplanes - rogercosseboom
http://www.popsci.com/scitech/article/2004-09/amazing-rusting-aluminum
======
jodrellblank
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
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.

~~~
jodrellblank
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.

~~~
mcaloney
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?).

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

------
timbowen
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.

------
mattmaroon
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.

~~~
noonespecial
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?

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

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

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

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

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

------
wallflower
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
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...](http://www.reddit.com/r/science/comments/85clw/why_mercury_is_forbidden_aboard_airplanes/c08ahms)

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

~~~
jcl
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...)

~~~
Xichekolas
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...](http://www.reddit.com/r/science/comments/85clw/why_mercury_is_forbidden_aboard_airplanes/c08agdw)

[http://www.reddit.com/r/science/comments/85clw/why_mercury_i...](http://www.reddit.com/r/science/comments/85clw/why_mercury_is_forbidden_aboard_airplanes/c08agl8)

~~~
JacobAldridge
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.

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

------
tjmc
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...](http://cleantech.com/news/1205/gallium-and-aluminum-
tigers-in-your-ta)

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

------
twopoint718
This makes me think of mercury as the Ice-9 of aluminum. Does anyone have
videos of this reaction?

------
raghus
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.

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

Jees.

------
tlrobinson
Or, you know, because it's toxic?

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

