Field of Science

The Sheri Sangji accident: The experimental details

Science has just published a summary of the report by California's Division of Occupational Safety and Health about the tragic accident involving Sheri Sangji and tert-butyl lithium. The summary is the most detailed description of the accident that I have seen so far and it makes it clear that there were at least four very significant violations of protocol during the experiment that Sangji was performing. These included:

1. Not wearing a lab coat and other appropriate safety gear.
2. Using a plastic syringe that by definition cannot be oven-baked to remove traces of moisture.
3. Using a syringe with a 2-inch needle that was about an order of magnitude shorter than the recommended length (1-2 ft.). This was a very significant safety breach since it would have required Sangji to tilt the bottle to extract the liquid, thus not only increasing the chances of a spill but also diminishing her general degree of control over the whole procedure.
4. Actually pulling the plunger back rather than let it be pushed by the inert nitrogen pressure from the bottle.

Of these four violations, only the first one can be easily assigned to Sangji herself since lab coats constitute a very general and well-known part of safety equipment. The others are specialized and specific to hazardous substances and their assignment is going to be much more ambiguous. The rub of the matter is going to be in finding out if these violations were the result of inappropriate or insufficient communication by the PI or an oversight on the part of Sangji herself.

From what I can tell, the report seems to lean toward the former possibility. One of the statements I found disturbing was Prof. Harran's admission that he "never discussed with Victim Sangji the risks associated with the tasks she was undertaking". Another important matter which I alluded to in a previous post was the responsibility of senior postdocs and graduate students in the lab, and the report provides a new twist to the issue that I hadn't seen before. Harran says that a postdoc in his group was supposed to train Sangji in the specifics of handling t-BuLi. The postdoc himself admits that he does not have specific recollection of providing "formal" training to Sangji. In addition Harran admits that he never confirmed whether the postdoc had in fact properly instructed Sangji in the use of the hazardous reagent. I would think that the relative apportioning of the blame between Harran and the postdoc is almost certainly going to be a focus during the trial.

None of this is too comforting and it certainly does not sound like it would make it easier for Harran to defend himself. And yet the sad fact of the matter is that this is how many labs around the world probably operate. The PI does not immerse himself in the minutiae of handling specific reagents and leaves it to the postdocs in the group. The postdoc or senior students in turn gingerly step into that notoriously gray area where it becomes difficult to say whether a particular degree of instruction was "sufficient" or not; for instance, was it enough for the postdoc to demonstrate the protocol once? How about twice? How about one actual demonstration followed by two pointed reminders?

These and other questions are almost certainly going to come up during the proceedings and their fuzzy, gray nature is going to make it difficult to assign blame. But the details of the report make it clear that somewhere, sometime, the crucial information undoubtedly slipped through the cracks. And even a clear admission of this fact may make practitioners around the world more vigilant and, one hopes, more humble.

15 comments:

  1. Is the postdoc facing any charges?

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    1. The legal statute refers to "Any employer and any employee having direction, management, control, or custody of ... any other employee." I'm guessing that the DA saw Harran as fitting that description--he hired Sangji, directed her work, and was ultimately in charge of his lab--but not the postdoc.

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    2. Thanks for pointing this out. The legal statute does make it clear, but for me the question still persists. Should the PI personally demonstrate every specific protocol to every student every single time? If not, how much responsibility do the postdocs to whom he has entrusted the actual demonstration shoulder? And what happens if the PI has told a postdoc multiple times to instruct a junior co-worker in a specific protocol and the postdoc simply fails to do this; is the PI still equally responsible?

      By the way, the legal statute as printed above includes the possibility of an "EMPLOYEE having direction, management, control, or custody of...any other employee". Wouldn't this include the postdoc?

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    3. It could, but he was never really assigned to supervise Sangji. She was just told to ask him for help. And he left the lab a month before the incident.

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  2. I said it before I'll say it again, how is safety going to be improved when the PI's are absent and responsibility left to a poorly paid, overworked and heavily casualized workforce (i.e. postdocs). It's in the postdocs interest to spend minimal time on actual safety issues, given the crushing bureaucracy, and concentrate on launching a career when. It's in the PI's interest to scapegoat the postdoc as much as possible as they are entirely expendable.

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  3. The comment, "Actually pulling the plunger back rather than let it be pushed by the inert nitrogen pressure from the bottle," is interesting. The SOP at UCLA, for example, describes another technique for dispensing t-butyllithium that does not pressurize the bottle using an inlet adapter. It states, "The goal of this technique [with the inlet adpater] is to equalize the pressure in the reagent bottle. A different technique is to use inert gas pressure to force reagent into the syringe, but that has the danger of blowing the plunger out of the syringe body and spilling out pyrophoric reagent." (http://www.chemistry.ucla.edu/file-storage/publicview/pdfs/SOPLiquidReagents.pdf) I tend to think that an inlet adapter is safer than pressuring a bottle; both are recommended by some manufacturers.

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    1. Even though I was taught to pressurize the bottle in grad school, I tend to think that the inlet adapter is the safer option as well--particularly for a syringe that large. The force exerted on a plunger in a 60 mL syringe is more than some people are able to manually handle. In fact, when I first heard of this accident, I'd assumed this is what had happened.

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  4. I like putting the bottle under minimal positive pressure with a dense gas like argon. A balloon attached to a cut-off syringe (with very high-gauge, tiny needle) works well. The gas in the balloon fills up the bottle as you withdraw the reagent, keeping moisture out.

    I have had nothing but bad experiences with glass syringes. They always seem precariously loose-fitting and capable of falling apart. I generally go with all-plastic syringes that I've "rinsed" with three flushes of argon.

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  5. Gas-tite syringes with Teflon on glass are the best (albeit expensive), as they don't wet the plunger like a glass syringe. With many organics, plastic syringes are problematic as the rubber tip at the end of the plunger might absorb or react with your reagent or solvent.

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  6. Yes, but there are plastic syringes that are all-plastic (no rubber). Sangji was using such a syringe.

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    1. In my lab we would routinely use all-plastic syringes for transferring reagents (with 6-inch needles and balloons/low pressure lines to equalise bottle pressure), and we did store them in an oven. Admittedly not as hot an oven as some of the glassware, but warm enough to keep them dry enough for most things, including small quantities of BuLi.

      That being said, anything in that kind of quantity wouldn't be a syringe job.

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  7. The fact that technical lab knowledge is all too often poorly transferred to those who need it is a serious and all-too-comon issue. I was fortunate enough to attend an undergraduate institution that took technical training seriously, but in graduate school (an Ivy league institution, no less), I found that educating the students was given hardly any priority. Graduate students were considered cheap, expendable labor. My advisor never checked to see if I knew what I was doing, or if I was becoming more proficient in those areas I needed to. From what I could see, my experience was fairly typical. Afterwards, I was employed in a capacity where I worked with new lab employees (mostly BS level), and I was stunned at the lack of effective technique among the new employees. What happened to Sangji was unimaginably tragic, but it was all but inevitable and, unfortunately, very likely to happen again.

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  8. How is this for criminal court? Shouldn't this be a matter of civil concerns? We live in a world where people can knowingly expose others to communicable diseases without consequence (you can withold or even lie about the presence of STDs and then infect someone else, without consequence), but this man can be persecuted for years (with taxpayers money) for a laboratory accident (I am not contesting the magnitude of the accident, but it was just that). She should have been wearing a lab coat. I am sure she knew that--I am not a professional chemist/scientist (as she was), and even I know that. And, in a laboratory, you are supposed to treat everything as potentially dangerous...just like you treat a gun as loaded at all times (even when you KNOW the gun is not loaded). Yes, this is unfortunate, but there is an element of respect you need to have in the laboratory, and while it is unclear whether or not her supervisors had that respect, it is very clear that she did not. It is unclear whether she was properly informed, but her response is also not guaranteed, as she demonstrated a disregard for basic laboratory practices in not wearing a lab coat.

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