"Almost as bad as the internet"

https://www.science.org/content/blog-post/alleged-dimethylmercury-incident

We had a weird story develop over the weekend here in the Cambridge area (and among organic chemists in general). I’m glad that I wasn’t trying to blog it as it happened, because it’s taken some turns!

This all started last Wednesday night, but most of us only heard something on Thursday when word came of an MIT chemistry building that was being closed off because of a report of someone who had been exposed to hazardous material. It became clear that said material was possibly dimethylmercury, which a graduate student had claimed to have synthesized, and who subsequently reported themselves to a local emergency room. And you can see why that caused a stir (but read on!)

Dimethylmercury is very, very bad news. It is obviously something I will not work with, but it’s never been the subject of a blog post here in that category because unfortunately there’s nothing lighthearted about the subject. Not after the death of Karen Wetterhahn in 1997. That story should be well known to chemists everywhere, but the short version is that Prof. Wetterhahn (at Dartmouth) was accidentally exposed in August of 1996 to a few drops of liquid dimethylmercury on her latex-gloved hand. What she didn’t know (and what none of really knew) was that this compound rapidly penetrates such gloves, which meant that Wetterhahn was exposed to skin contact within seconds. Toxicologically, it is probably the worst of the organomercurys, which are of course a dangerously toxic group of compounds overall. Her precautions for handling the compound were the standard at the time, it should be noted.

Prof. Wetterhahn began to notice general symptoms within weeks. Early in 1997 she began to show neurological problems, and within weeks she had collapsed into a vegetative state. She was removed from life support in June. She had very high levels of mercury in her blood, and all attempts at chelation therapy to remove it were ineffective. That’s surely because it had spread throughout her body by the time the problem was recognized, but frankly no one can be sure if there were any measures that could have been effective enough after the initial exposure. This horrifying incident led to a complete re-evaluation of the use of dimethylmercury in synthetic and analytical chemistry, where among other things it had been the reference peak standard in mercury NMR experiments.

No one should be synthesizing this compound and no one should be working with it at all. I cannot think of any scientific result it might offer that is worth the risk or where no alternative route can be found. So you can see why the MIT incident made everyone jump! But subsequent updates have made the situation rather more complicated. On Saturday, the university said that “emerging information called into question whether this compound was in fact synthesized”, and also that the student’s blood work had shown no signs of mercury exposure. Which is good to hear. The university has re-opened the lab building as of today.

What we don’t know is what this student was up to: why they seem to have thought that they needed to synthesize dimethylmercury and what chemistry they actually performed. I don’t know when we’ll find out more details - if we ever do - but the fact that the building and lab are open again today makes a person think that there wasn’t any actual attempt at all. You can’t make dimethylmercury without going through some other pretty damned toxic species and generating a very serious waste stream, and I find it hard to believe that this could be cleaned up so thoroughly, so quickly. Mercury is of course easily detected to very low levels with decent analytical chemistry equipment, which MIT has plenty of. So my conclusion is that the main problem here is likely not a synthetic chemistry one, but I will be very glad to hear more details.

In case it’s needed, though, a word to anyone who is still intrigued by this compound: synthesizing or working with dimethylmercury at this point is not cool, edgy, transgressive, or something to impress the crowd with. It is a wildly stupid idea that will endanger your life and the lives of anyone unlucky enough to be around you while this work is going on. Not to mention anyone who is simply unlucky enough to be downwind. It’s like working with homemade nerve gas, but at least that kills you quickly. With compounds like this, everyone knows the dangers, and honestly - I’m going to be offensive here - it’s hard not to think that anyone who goes ahead after knowing them deserves what they get. I’m glad that this MIT student is OK, because I’m glad in general when someone is saved from a horrible, inexorable death. But come on.

https://www.science.org/content/blog-post/alleged-dimethylmercury-incident