From: davivid <davivid**At_Symbol_Here**WELL.COM>
Subject: Re: [DCHAS-L] Opinion: What I learned from my lab accident
Date: Wed, 22 Jun 2022 11:49:53 -0700
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Message-ID: 50ea85d7-583a-33af-20f0-8ef206806a22**At_Symbol_Here**well.com
In-Reply-To


I think anyone who has spent a few years in a lab has heard their share
of "horror stories", and probably experienced some first hand. These are
wonderful teaching aids as they underline the details that you need to
look out for and highlight the consequences when they are overlooked.
They are best combined with lessons learned.

I think these are a great way to start a safety meeting.

Here are a couple

(not me) A researcher was trying to grind a material in a ball mill, but
the material was too soft. So they cooled it down by adding liquid
nitrogen to the container, clamped the lid on and proceeded to grind.
Their supervisor happened to notice frost on the ceramic mill and asked
about it. On hearing what had been done they grabbed the researched and
hit the deck. The mill exploded soon after sending heavy ceramic
fragments flying. Lesson learned: Don't add cryogens to closed systems.

(not me) A researcher was evaporating a volatile solvent using a rotary
vacuum pump protected by a liquid nitrogen trap. They lowered the dewar
to check the solvent level in the trap but the vacuum tubing was twisted
and flipped the trap upside-down sending the condensed solvent into the
still running pump. The solvent flashed to vapor on contacting the hot
pump oil and split the pump casing at the casting seam. Lesson learned:
vacuum tubing can be difficult to work with but it is important to
connect it without kinks or other stresses.

(A fellow I worked with) A researcher added a small amount of acetone to
a new, empty glass waste container labeled for acid waste. A short time
later someone added nitric acid. BOOM! Fortunately the cap blew off
rather than the bottle shatter. Lesson learned: Pay attention to labels.

(a fellow I worked with) A researcher withdrew a sample of a heated
reaction mixture from a flask using a 1 mL syringe. They tried to
transfer the sample to a vial but the mixture had cooled and solidified
in the 30 gauge needle. Applying force to the plunger resulted in the
luer needle popping off the syringe and spraying hot phenol in their
face. Fortunately they had no lasting injury after hitting the eyewash.
Lessons learned: It is remarkably easy to produce surprisingly high
pressures by pressing the plunger of a small diameter syringe. Luer
connections are friction fit, Luer lock are more secure. Protect your
face/eyes. Hot stuff cools quickly in high surface to volume containers.

(Me) I was asked to scale-up a reaction to produce a kilo of so of an
intermediate. The reaction was simple, heat triethyl phosphite with an
aromatic halide in the presence of a catalyst (Arbuzov reaction). The
usual catalyst was palladium but we didn't have enough for this prep so
I used nickel. Since nickel was known to be substantially less reactive
in this reaction than palladium I increased the amount. The reaction
proceeded well at first but then started flooding the condenser. The
solution would have been to cool the reaction in ice/water but the
equipment filled the entire height of the hood. All we could do was turn
off the heat, close the sash and wait. The reaction was completed by
erupting out through the condenser. After cleanup I managed to achieve
an 80% yield. Lesson learned: Reactions in general and catalysts in
particular do not scale linearly. Also, leave room to lower the heating
bath/mantle and bring in an ice bath.

That's all for now.

Cheers!
Dave lane
Principal
Clavis Technology Development

On 6/21/22 8:12 PM, Schroeder, Imke wrote:
> I would be interested in contributing also. I have my own personal story and many others to share.
> My best,
> Imke
>
> From: ACS Division of Chemical Health and Safety on behalf of Ralph Stuart
> Date: Tuesday, June 21, 2022 at 6:30 AM
> To: DCHAS-L**At_Symbol_Here**Princeton.EDU
> Subject: Re: [DCHAS-L] Opinion: What I learned from my lab accident
>> Would anyone be willing to contribute their lessons learned to such a symposium at a national conference if I organized it?
>
> I have a new personal one ready to go when the symposium comes up. I wrote it up for the ACS Chemical Health & Safety special issue on Shifting Culture from Blame to Gain: A Call for Papers to Openly Discuss Chemical Incidents described at
> https://pubs.acs.org/doi/10.1021/acs.chas.2c00031
>
> That issue is likely to be a good source of similar presentations.
>
> - Ralph
>
> Ralph Stuart, CIH, CCHO
> ralph**At_Symbol_Here**rstuartcih.org
>
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