Dimethyl Mercury Exposure Incident at MIT • Hacker News Board

Re: Dimethyl Mercury Exposure Incident at MIT

#81

Post by lstodd » Tue, Sep 01, 2026, 4:38 PM UTC

gilleain wrote: post #12

manarth wrote: post #11

Other "sources" (using the word loosely as their provenance is unclear) > "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] Karen Wetterhahn's exposure and death [3] is a cautionary tale of the extreme toxicity of dimethyl mercury, and wa…

Yes, dimethyl mercury is terrifying stuff - it killed Karen Wetterhahn from a few drops that went _through_ the gloves she had on: > 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])

Sufficiently pure dichloromethane is also fun stuff. It just eats through most any gloves, plastics, whatever. Even PET, and only polyethylene is somewhat resistant.

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.

Re: Dimethyl Mercury Exposure Incident at MIT

#82

Post by YakBizzarro » Tue, Sep 01, 2026, 7:33 PM UTC

j_seigh wrote: post #78

gavinward wrote: post #16

Earlier quoted context omitted.

I think Hydrofluoric acid is probably the substance you're describing which leaches the calcium out of your bones. It will certainly burn you too though. It's a common byproduct from heating fluorinated gases and is sometimes used in its own right for wet etching. As an aside, I love it when they tell you in the safety WBT what the highly toxic gas smells like.

Some places would mix it with nitric acid so the yellow stain would tell you that you had been exposed. 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 diox…

Silane is like Methane, but with Silicon instead of Carbon (SiH4). Thanks god for doping was used Phosphine (PH3) and not Phosgene (COCl2), both are nasty, but the second is more. Plus I don't know how much is used, since nowadays doping is typically done by ion implantation rather than gas diffusion

Re: Dimethyl Mercury Exposure Incident at MIT

#83

Post by pvaldes » Tue, Sep 01, 2026, 9:32 PM UTC

No traces of the precursors. No stuff in the blood. Looks more like a stunt designed to spread panic (or likes?), than a real event. In both cases the student has a lot of things to explain.

Re: Dimethyl Mercury Exposure Incident at MIT

#84

Post by j_seigh » Wed, Sep 02, 2026, 1:21 AM UTC

YakBizzarro wrote: post #82

j_seigh wrote: post #78

Earlier quoted context omitted.

Some places would mix it with nitric acid so the yellow stain would tell you that you had been exposed. 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 diox…

Silane is like Methane, but with Silicon instead of Carbon (SiH4). Thanks god for doping was used Phosphine (PH3) and not Phosgene (COCl2), both are nasty, but the second is more. Plus I don't know how much is used, since nowadays doping is typically done by ion implantation rather than gas diffusion

Not enough caffeine. And yeah, it would have been phosphine since it was phosphorous that was the dopant.