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.
Update 2: The always excellent Derek Lowe with a further discussion of what seems now to have (thankfully, hopefully) been 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.
3 comments:
The thing that also alarms me with the HF incident is that the two students rushed in to assist were also injured. Training sufficient to overcome the human nature to help and avoid becoming the second or third victim must be conducted and reinforced. Glad it was just minor injuries for those students, but still a tragedy.
Also while working at a major research university a graduate student working with Hg salts became worried about possibly having synthesized dimethylmercury after switching reagents/solvents and spilling some. We (PI and me as Safety Officer for the University) were pretty familiar with the process and were confident that dimethylmercury had not been made but sent the student to the health clinic for bloodwork (everything came back negative). I would have still wished experimental changes were discussed with us beforehand, but it did help build trust and more communication happened after. I applaud MIT for sharing the details of the event, I don’t think there was anyway our university would have allowed anything to have been shared.
I want to reiterate that it is not just training but continuous practice and drills that can help overcome the urge to help others and rush into a dangerous situation. Slides that get reviewed once a year or first aid training with a refresher every two years where you declare scene is safe/secure before starting CPR on a dummy is not sufficient. For those that work with these extremely hazardous chemicals it is a privilege that you earn by demonstrating the highest skill and safety standards.
I’m curious about Rice University, is working with these extremely hazardous chemicals a privilege or just check the box? Also do you feel your safety department would demonstrate the same level of transparency as MIT?
Much training (natl lab) is not meant to work, but is meant to allow management to wash their hands clean in case something happens. "They were appropriately trained, so it's them, not us."
Post a Comment