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Previous by Date: Subject: 4 Re: [DCHAS-L] UCLA Lab Fire Date: Mon, 5 Jan 2009 16:06:41 -0500 Author: List Moderator |
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While I have no knowledge of the UCLA situation other than what we have all read, I have firsthand knowledge/involvement of several laboratory accidents that were reported in the press. I can say that in none of these were the printed reports anywhere near correct. Which has led me to basically not take anything I hear in the media as a fact.... SPECULATION: ON It is easy to imagine that the worker could have pulled the plunger all the way out. For example, if he/she needed 10 mL and was using a 10 mL syringe (or got a little creative and tried to draw 11 mL in one fill). And if that happened, then you would have 10+ mL of hexanes burning on your hands, with a stream spewing from the syringe and inverted bottle. =46rom there, you could easily spray it on yourself or panic and drop the bottle.... It is also possible that the worker did not appreciate the pyrophoricity, and so I will relate a similar story in both these veins. This incident occurred a bit over 20 years ago. SPECULATION: OFF A former lab mate of mine needed to do a routine deprotonation reaction. He went to the fridge looking for a bottle of n-BuLi. He couldn't find any, but he did find a bottle of t-BuLi. Apparently, he thought "n-BuLi, t-BuLi, eh, it's all the same", and he decided to go with it. Before we go further, I should note that's a bad inference. I got some n-BuLi on my hand once. It was a bit warm and slippery feeling, but it didn't spontaneously inflame. t-BuLi is a whole other ball of wax. It *will* spontaneously inflame, period. There is no margin of error with it. Both of these come in Aldrich Sure-Seal=99 bottles, which I have affectionately nicknamed the Aldrich "Suuuuure, it's sealed" bottle. For those of you unfamiliar with the closure, it has a flat circular rubber septum underneath what is essentially a standard beer bottle metal crown cap that has a 1/4" hole in it so you can stick your syringe through the septum and into the bottle: http://www.sigmaaldrich.com/chemistry/solvents/bottles-and-cans.html#sure There's an unfortunate tendency to buy alkyllithiums in large bottles, but use them in small amounts. So if you have a 500 mL bottle of 2.0 M t-BuLi in hexanes and it's been around a while, that septum starts to give out. It becomes second nature to plug the hole with some Parafilm and strap that down with more Parafilm until you can't even see the seal or septum. I'm not endorsing this kind of jury-rigging, just explaining what the practice in that lab was. To dispense the reagent, the procedure is 1) fill the syringe with a volume of nitrogen equal to the volume you wish to withdraw 2) inject that into the bottle, 3) invert the bottle, 4) draw the desired amount into the syringe, and 5) withdraw the syringe *after* tilting the bottle to the side. The reason for the tilt is that if the bottle has been over- pressurized and you withdraw the syringe while the bottle is still inverted, and the liquid inside can either leak out or spurt out, depending on the condition of that septum. So, back to our story.... Nameless Labmate proceeds with his reaction. He withdraws the syringe from the bottle while it is still inverted, and the moment he does, a stream of burning t-BuLi sprays itself all over the benchtop. This, in itself, was actually no big deal, as it would simply burn itself out. But Nameless had a stream of consciousness that went along these lines: "Aiiiiggghhh, fire. OK, OK, OK, I am working alone in the lab at the moment, I must go pull the fire alarm." Which is not a bad thought, except that he put the bottle of t-BuLi down ***on the burning bench top***. He runs out to pull the fire alarm, in the meantime, the bottle of tBuLi is spewing flames and igniting a pretty hairy mess. About that time, someone else came in and put the whole mess out with some Class D powder. We later found an intact container of toluene on that benchtop that had a big char mark on it, so, basically, Nameless missed having a Major Incident by about 30 seconds. NOTE: I missed seeing the event happen, but arrived on scene about 10 minutes later. There are lessons learned here, and that's the point of the story: 1. I have found that most accidents are due to complacency, either during routine operations or "just cleaning up". Accidents with t- BuLi are incredibly rare because the laboratory worker is made painfully aware of the incredible power/reactivity and the precautions that must be taken. However, if the first step - Hazard Communication, is skipped or the worker doesn't appreciate the dangers, then you have incidents like the one I just described. 2. Part of that Hazard Communication means explaining how to set up for a t-BuLi reaction and the possible problems. Which means proper use of the reagent bottle, clearing all flammables and clutter out of the work zone, having a bucket or something to put the bottle in if there's a problem, having a Class D extinguisher immediately available, performing the reaction with an experienced co-worker available, thinking through what to do if you encounter a flaming stream of liquid, PPE, doing this in a hood rather than on an open bench, knowing the location of the shower etc. 3. Purchasing reagents in amounts far larger than you need because "it's 5 times as much for $3 more" is a false economy as far as disposal costs go, but this incident highlights the danger involved with purchasing large volumes of pyrophoric reagents that are used infrequently. Peroxide-formers get similar shout-out on this point. 4. People vary widely in their reactions to an emergency situation, no matter how good the training, and no matter their level of learning. About half will respond and automatically do what needs to be done, and the other half will simply panic, freeze, or focus on one single aspect of the situation. This is an extremely difficult issue to overcome, and experience is, alas, the best teacher. As part of all training, we must instill on laboratory workers to think "what would I do it..." whenever they plan and execute an experiment. The research director should be sure to ask questions like this of his/her laboratory workers while they're working. It not only demonstrates the culture of safety mindset, it instills on workers/students that when we plan an experiment, we address *all* considerations whether it they be yield, %ee or safety. Additional reading here: http://www.ilpi.com/msds/ref/pyrophoric.html and links therein. Regards, Rob Toreki On Jan 5, 2009, at 1:59 PM, Laurence Stock wrote: > What does "the stopper on the syringe came undone" mean???? > > There are no stoppers on a syringe??? Do they mean plunger not > stopper?? Was the plunger completely pulled out?? > > > > On Jan 5, 2009, at 12:21 PM, List Moderator wrote: > >> http://www.dailybruin.ucla.edu/news/2009/jan/01/research-assistant-burned- chemical-fire/ >> >> Research assistant burned in chemical fire >> >> written by Anna Andersen >> Published: Thursday, January 1, 2009 >> A 22-year-old research assistant at UCLA remains in stable >> condition after a chemical fire left her with second- and third- >> degree burns on 40 percent of her body on Monday. >> >> The victim, whose identity has not been revealed, was working with >> T-Butyl lithium, a pyrophoric compound which caught on fire when it >> was exposed to air, said James Gibson, director of UCLA >> Environment, Health and Safety. >> >> While she was extracting the compound, the stopper on the syringe >> came undone and exposed the chemical to air. >> >> Gibson said he did not know how the stopper came undone but said >> the syringe was found melted. >> >> "This kind of accident is very rare," he added. >> >> The fire, which occurred in the Molecular Science Building, was >> reported at 2:57 p.m., according to a report by Melissa Kelley, a >> spokeswoman for the Los Angeles Fire Department. A fellow research >> assistant was able to put the fire out with water before the fire >> department arrived, and there was no structural damage to the >> building. >> >> The victim has since been transferred to the Grossman Burn Center >> in Sherman Oaks and remains in stable condition, Gibson said. >> > ======================== ========================= ===== Safety Emporium - Lab & Safety Supplies featuring brand names you know and trust. Visit us at http://www.SafetyEmporium.com esales**At_Symbol_Here**safetyemporium.com or toll-free: (866) 326-5412 Fax: (856) 553-6154, PO Box 1003, Blackwood, NJ 08012
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