Dimethyl Mercury Exposure Incident at MIT
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https://www.science.org/content/blog-post/alleged-dimethylme... ("The Alleged Dimethylmercury Incident")
Seems the initial reporting may have been misleading. There was apparently *no* dimethylmercury exposure, after all: and MIT doubts it was synthesized in the first place.
Is this accurate? I read the original Wetterhahn report (it's the first search result on Google) and chelation did appear to reduce whole blood mercury, but didn't do anything for the CNS exposure.
That would be important because it suggests immediate Succimer treatment could avert fatal CNS exposure (it takes hours/days for the blood/brain transfer to occur, apparently).
Obviously, not an expert.
https://www.tandfonline.com/doi/full/10.1080/24734306.2020.1...
There are also some studies suggesting that the amount of excess mercury in fish compared to selenium may be more relevant than the absolute mercury concentration in causing potential toxicity.
> "based on the information available, this was a localized issue with only one student directly exposed. Their reported use of dimethyl mercury was unauthorized. MIT does not allow the purchase or synthesis of dimethyl mercury." [1]
[1] https://www.reddit.com/r/mit/comments/1w12gb9/dimethyl_mercu...
[2] https://www.nbcboston.com/news/local/hazmat-crews-respond-to...
> The case proved that the standard precautions at the time, all of which Wetterhahn had carefully followed, were inadequate for "super-toxic" chemicals like dimethylmercury
(from the Wikipedia page [3])
There aren't really any "good" organometals, but if there were, they wouldn't be this stuff.
LD50 about 2mg/kg oral. By oral it's meant that well.. if you soak your hands in it it will be worse.
Still it's the goto thinner for f/ex gluing ABS. I have a couple liters sitting on the shelf right beside me.
Holy hell. I would've have believed it was possible for a non-biological substance to be so toxic.
From https://en.wikipedia.org/wiki/Cyanide_poisoning
> A fatal dose for humans is on average 1.52 mg/kg of body weight
Assuming 80kg(175pounds), that's like 120mg of Cyanide.
There is probably even more nasty stuff.
You may also be thinking of phosgene, which actually contains no phosphorous at all. But it is extremely toxic see the LC50: https://en.wikipedia.org/wiki/Phosgene
I guess it's a biological product, but it's certainly not "living".
Then there's carfentanil and similar which are deadly only at much higher 100 microgram levels.
By the time I first took chemistry classes, though, that practice had stopped, less out of concern of exposure to liquid mercury and more for accidental exposure to gaseous forms due to spills.
One way to familiarize students with mercury was to have several liters of it in a wide open-top jar and have them force their fist through the mercury pool to the bottom of the jar.
In fact, forcing one's hand through mercury between six to eight inches deep is not easy, some kids found it too difficult to do.
I'd describe my hand as feeling very squeezed and it being forced upwards to the surface with considerable force. The experience was certainly unforgettable.
There were some safety protocols: good ventilation (to minimize Hg vapor) and afterwards hands had to be thoroughly scrubbed with soap and water.
> Emerging information calls into question whether this compound was in fact synthesized.
> while the student remains under medical supervision, their initial blood test result, which was received today, shows no sign of exposure to mercury.
Taken from https://emergency.mit.edu/
> If the MIT student was doing some work with reactive stuff and mercury and got an unknown result well outside expectations out of the output they were expecting i can see them struggling through working out what it could be, coming to the conclusion Dimethylmercury was possibble as an accidental side product of what went wrong, and just pulling all the emergency handles to be safe. Given how nasty that stuff is that is exactly the kind of reaction to such a scenario you'd want someone to have.
However, since it was an active silicon manufacturing plant, all employees and contractors were obligated to complete safety training sessions. And I swear now that these safety sessions were designed to weed out the faint-hearted guys who weren't serious about supporting this silicon brand.
The safety sessions were simple lectures, with some handouts and PowerPoints, and some of the chemicals they described were absolutely insidious stuff. They were colorless, odorless, and some could melt or disintegrate bone without noticeably affecting the skin or muscles. They said you would just end up with a limp and useless appendage if you spilled some of this stuff on you. Other stuff was highly toxic and you didn't want to breathe anything. Basically it was a big warning to just stay out of the manufacturing floor, especially if we didn't know what we were doing.
I never went near the manufacturing floor. It was a pretty cool job and I wish I lasted longer there. They couldn't scare me away with a safety session, since my Dad had worked for decades in Environmental Health and Safety. Dad knew all about the nastiest stuff and he was always responding to hazardous laboratory accidents. Dad made us the safest home in our ZIP code.
As an aside, I love it when they tell you in the safety WBT what the highly toxic gas smells like.
Fwiw, there is a BurnBuster brand of fire extinguisher for stopping lithium runaway. See ASIN B0DZ9R7Q51. It is a ripoff but probably good to have.
Single use ones too can contain fluorine, but not the runaway risk. Nevertheless, they require significant care to avoid shorting during storage. Never store them loose or where they can contact each other. Tape them well from all sides, and put them in a sealed ziploc bag before disposing.
Other fun chemicals used in fabs were Silane (CSi4), methane w/ silicon instead of hydrogen, used to form a silicon dioxide layer for etching* w/ HF and final step of protection. It would spontaneously combust on contact with air, so when you popped a tank fitting it would leave a white powder residue. Silicon dioxide is used as a food additive so AFAIK that wasn't dangerous.
Phosgene was also used as a dopant. If the alarm for that went off you really got out ASAP.
Arsine was a dopant also.
This is what I sort of remember from working on slacker job in silicon fab a long time ago when the number of transistors per chip was 1. I did say a long time ago.
* You could also just oxidize the outer layer of the silicon wafer itself w/ water vaper at high temps.
https://www.chemistryworld.com/opinion/a-risk-not-worth-taki...
(Well, the poor woman, then, this article ...)
> One problem with this subject is that it tends to lead to bragging contests about who has run the most hazardous reactions. But think about it: if these reactions have all been run for good reasons with the best protective equipment there is less to brag about. And if they haven’t, then the discussion turns into figuring out who has been the biggest fool
I suspect the answer is "bragging rights" in this case.
Some guy's in the hospital from handling droplets of instant liquid death and they're worried about feelings being hurt?
https://old.reddit.com/r/labrats/comments/1w1ukrv/mit_studen... ("A message sent out from the chair of the department of chemistry...")
>To keep Reddit safe, accounts are required to access old Reddit.
God, I hate that horrible website. How does this keep people "safe"
> "A message sent out from the chair of the department of chemistry at the school identifying the substance in question:"
> "“Dear Chemistry Colleagues,"
> "I am writing to provide an update on efforts to reopen Building 18 safely."
> "A specialized team from Triumvirate Environmental worked overnight on decontamination efforts in the building. This work includes wipe-downs of relevant surfaces in the lab and common areas, as well as the safe disposal of items that may have been contaminated. Decontamination work will continue throughout the day, and the building will remain closed until the work is complete."
> "In addition to our health and safety experts, we have been working continuously with staff and colleagues from departments across the Institute. Our highest priority is community safety, and we continue to make decisions accordingly and gather as much information as we can."
> "It remains the case that, based on the information available, this was a localized issue with only one student directly exposed, and this student was the individual working with the compound. Their reported use of dimethyl mercury was unauthorized. MIT does not allow the purchase or synthesis of dimethyl mercury."
> "I want to reiterate that, based on the information available to me, our industrial hygienists, MIT Health medical experts, and other resources we've consulted, the risk of secondary or tertiary exposures remains low, given the compound's characteristics and the information available to us."
> "Please feel free to reach out with questions. I will continue to provide regular updates as we learn and have more to share."
> "With care and regards,"
> "Matt Shoulders”"
To detect elemental mercury vapor, the air is drawn in to a controlled chamber where if present it amalgamates with pure gold as the reference (zero) material, and determined electronically.
I don't think this works with organic mercury like dimethylmercury. It is an organo-metallic compound and behaves very unlike elemental mercury.
I'd be running the AA's from the analytical labs in mercury-vapor mode, putting them on carts if necessary since they do not need gas supplies for mercury detection & measurement.
Before plasma-emission spectrometers became widespread, more people were familiar with the traditional atomic-absorption (AA) instruments.
Instead of measuring the combined emission of any elements present in the sample, the AA used the steady emission of the target element alone as reference, from a (expensive) lamp having that specific element present within its hollow cathode.
AA normally uses a clean acetylene flame to vaporize the sample, with the reference light beam passing above the flame. If the target element is present in the sample, it absorbs some of the characteristic wavelength from the beam and is detected as a negative deviation from baseline.
For trace mercury though, the flame was not good enough, so an even more expensive and complex graphite furnace was installed in place of the burner.
Either way the light beam passes through a few inches of lab air to get from the lamp to the optical detector.
And you don't need the burner or the furnace to detect things that are already vaporized.
The graphite furnace would be good to calibrate with later if you couldn't do it in advance.
I wonder if their contractor has as good detection ability as MIT itself.
I hope it was worth working with such a notoriously unsafe compound against regulations and all sense.
https://en.wikipedia.org/wiki/Karen_Wetterhahn#Accident_and_...
I guess the student just needs to hope their exposure was incredibly minute, otherwise they really have only a hard death to look forward to.
"Emerging information calls into question whether this compound was in fact synthesized. We are also able to disclose, with the student’s permission, that while the student remains under medical supervision, their initial blood test result, which was received today, shows no sign of exposure to mercury."
Is there some interesting aspect which danger aside might motivate this or was it just a dick move? Were they possibly motivated for bad reasons, seeking to commit harm?
https://sites.northwestern.edu/ohalloran/199hg-nmr-standards...
This MIT incident was in a chemistry building that has been in use since 1970, so it could have been accidental release of an old, unused container or sample tube of the material.
> "Can't imagine why"
Put that in perspective against industrial quantities where a hardhat operator opens the hatch on a very full compartment of a chemical tanker, looking at their mirror image reflecting up from the surface of a few hundred tonnes of cargo a few feet below.
Which is then carefully sampled and delivered to a lab where they check for trace water in the benzene.
Edit: reading further down the comments, Derek Lowe is guy.
If you’re testing for dimethyl mercury in say fish, you need a standardized sample of dimethyl mercury to run.
These references are highly dilute and thus less hazardous. But some labs prepare their own references rather than buying them.
That requires working with pure dimethyl mercury.
The hazard is manageable as long as you’re prepared. Chemists work with lots of hazardous chemicals and it can all be managed with the right preparation.
Sorry for the confusion—I know it's weird but the alternative turns out to be even more confusing and we've never figured out how to square that circle!