Date: Mon, 05 Jan 2009 14:17:54 -0500 From: "Margaret Rakas"
Subject: Re: [DCHAS-L] UCLA Lab Fire >What does "the stopper on the syringe came undone" mean???? Having worked with these MANY years ago, my guess is that the reagent bottle was pressurized (nitrogen) and so the material in the syringe was as well; the barrel (or plunger) then has a tendency to push itself out. I had strong hands from tennis and playing piano, but sometimes the researcher doesn't, or isn't aware of the pressure differential and is caught by surprise. You can kinda tell you'll have to hang on harder (or use a nitrogen bubbler to get the pressure down a bit, although I'm not sure the chemists would go for that) if you put the syringe in and the barrel starts to go back quickly even before you start to draw material. I am kind of surprised they used water to put out this fire, though...unless it became a big one. Other than being prepared for this happening (so have someone to help you hold the syringe, have the fire extinguisher nearby, prep the bottle with a small amt of nitrogen through a bubbler if it seems like the material is REALLY pressurized)--does anyone have anything else they'd do? My personal opinion only, not legal advice, and may not be the opinion of my employer or any group to which I belong... Margaret == Subject: RE: [DCHAS-L] UCLA Lab Fire Date: Mon, 5 Jan 2009 13:25:14 -0600 From: "Nail, John" Pyrophoric substances such as t-butyl lithium are stored in septum- capped bottles and transferred by either syringe or transfer tubes under positive inert gas (usually nitrogen, can be argon) pressure. The procedure when syringing is to insert a needle attached to a low pressure nitrogen or argon line into the septum, insert the syringe into the septum, then use the positive pressure from the inert gas to transfer the solution into the syringe. This keeps the solution under an inert atmosphere and prevents air from entering the bottle and decomposing the reagent. There appears to be two likely explanations for this incident: 1) The pressure on the inert gas line was too high, resulting in blowing out the septum, or 2) Either the pressure on the inert gas line blew out the syringe plunger or the victim inadvertently pulled it out of the syringe. Due to their nature, pyrophorics are hazardous. The ONLY ways of minimizing incidents are proper training and proper attention by the lab workers. Even when everyone is properly trained and working as they should, fires will occur; these are unavoidable. I note that this is the first working day of the year; it can take a day or two to get a person's head back into the lab. John Nail Associate Professor of Chemistry Oklahoma City University == Subject: RE: [DCHAS-L] UCLA Lab Fire Date: Mon, 5 Jan 2009 14:24:37 -0500 From: "Bush, Kimberly" I noticed this odd description as well. I initially assumed that stopper meant plunger. Based on the following explanation . . . " 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." I think . . . The phrase "extracting the compound" must mean that she was pulling the pyrophoric reagent through a septum on the original container using a needle/syringe. The reason for using a needle through a septum, of course, is to avoid exposure to air. It is very likely that the needle became clogged due to precipitate (solids) in the reagent or that she did not have a vent needle (or nitrogen line) in the septum to allow for gas to back fill the volume being removed from the container. Another possibility is that the needle being used was too small of a gauge to easily pull the liquid. Any one of the above situations would obviously make it very difficult to pull the plunger. A common rookie mistake is to pull like crazy on the plunger to try to suck up more liquid. A sudden release of this pressure (needle un clogs, air gets sucked in through hole in septum, etc) and the plunger may pop out of the syringe. The uncontrolled nature of this event means that chemical will spill or spray into the air where it is likely to ignite. It could also be that the needle, which is usually secured to the syringe via a luer-lock (screw-on) type connection, came unscrewed while she was pulling the reagent out through the septum and the chemical leaked from the syringe and or needle, causing fire. The pressure then may have then blew out the plunger. Just my thoughts from the research chemist perspective! Kimi Bush Staff Chemist Med Chem Safety Committee Co-Chair Merck & Co. Inc. WP14-3 770 Sumneytown Pike P.O. Box 4 West Point, PA 19486 ofc: 215-652-2766 cell: 610-223-9227 fax: 215-652-3971 == Date: Mon, 5 Jan 2009 12:58:33 -0600 From: Jason Jones Subject: Re: [DCHAS-L] UCLA Lab Fire The question I would like to know is: How much water did the fellow researcher assistant use to put the fire out since the material is water-reactive to begin with? Jason Jason Jones The University Of Mississippi Medical Center Biological/Chemical Safety Officer Phone: (601)-984-1981 Pager: (601)-929-3884 jnjones2**At_Symbol_Here**hr.umsmed.edu
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