Lab safety - seriously, be careful out there

This past week was a genuinely horrific reminder of the importance of lab safety, especially in the realm of hazardous chemicals.  

First, a graduate student at Hokkaido University was killed due to some kind of large-scale exposure to hydrofluoric acid.  For those who don't know, HF is used at some rate in semiconductor-related work, because it's a way to etch SiO\(_2\) from silicon surfaces and leave a hydrogen-terminated surface.  (Usually this is done using buffered oxide etch, which is less concentrated than the pure acid but still must be handled with great care and appropriate personal protective equipment.)  Accidental exposure to small amounts of HF is not always immediately obvious, because it is not that aggressive in damaging human skin (unlike, say, nitric or sulfuric acid).  Rather, it attacks the calcium in bones (as well as screwing up many other biological processes).  The topical treatment is calcium gluconate gel, which can help by being a much more readily accessible source of calcium ions to bind with the fluoride ions.  There are no real details out yet about how someone had a massive amount of HF splash on their head/face, but that sure sounds like a terrible case of poor storage and handling practices.  

Then it came out that this past Wednesday a doctoral student at MIT had been exposed to dimethyl mercury.  Here is a reddit discussion thread in r/mit, and here is another one on r/chemistry.  Apologies for the reddit links, but there doesn't seem to be any news reporting about this yet.  From the MIT announcement in those threads, it was in building 18, and decontamination of the space is ongoing.  Any scientist of my generation knows about dimethylmercury because of the horrifying death of Dartmouth chemistry professor Karen Wetterhahn in 1997.  She was exposed to tiny drops of this stuff, which diffused through her latex gloves (which she did not realize at the time).  Prior to her death, people still occasionally used dimethylmercury as a standard in NMR measurements.  Organic mercury compounds are widely recognized as incredibly dangerous because tiny amounts can lead to mercury crossing the blood-brain barrier, leading to terrible neurological systems and death.  Once mercury is into organic tissues, it is very difficult to chelate the metal ions.  Again, there is a shortage of official information about this incident, but MIT's announcement made it clear that any synthesis or use of this compound is not permitted and was unauthorized.  Update:  the latest from MIT’s emergency response page raises the possibility that there may not have been any exposure or dimethylmercury present.  Fingers crossed that this turns out to be a false alarm.

To students reading this:  PLEASE be careful in the lab.  Know the hazards of what you're doing, and use appropriate procedures and protective equipment.  If you ever have questions about safety, for goodness' sake please ask.  Your PI and your environmental health and safety team would far rather have you ask questions and be cautious then to do something dangerous.  No PI should ever make students feel like thinking about safety is unnecessary or overly cautious, and no PI should ever be hesitant about supplying or letting students purchase PPE.