DCHAS-L Archives, Mar 22 2022 - Re: [DCHAS-L] OSHA materials on Karen Wetterhahn's mercury exposure

Amazing work to all in finding all the references! It brings me back.

The toxicity of dimethyl mercury was no secret to Karen and many (hard to ignore Minimata disease). The guidance on the SDS was certainly lacking but as many have offered - it was par for the course at the time. The current SDS is much more clear and direct as a result of this:

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Personal protective equipment

Eye/face protection Face shield and safety glasses Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).

Skin protection Highly resistant laminate gloves under a long-cuffed neoprene or nitrile glove. Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.

Body Protection Complete suit protecting against chemicals, Flame retardant antistatic protective clothing., The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.

Respiratory protection Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

Control of environmental exposure Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

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I wonder how many of the chemicals on the market today have been permeation tested? Do all of the SDS sheets have the most recent info?

Unfortunately, my experience with some chemists of the era was that some form of risk-taking was required to advance science. I suppose the same debate is ongoing around precautions for crisper cas9 or nanoparticles today. I remain optimistic that risk assessment is becoming part of science education as an invaluable step in research and teaching and that our sources of data are ever-improving. It still often comes down to awareness of risk, human behavior, and resources.

Thanks

Michael

On Tue, Mar 22, 2022 at 1:32 PM Ralph Stuart <ralph**At_Symbol_Here**rstuartcih.org> wrote:

> if I remember correctly the chemical was actually synthesized for Sigma by a subcontractor in his garage that used Silvershield but his glove selection was not noted until after the incident.

I wonder who writes the (M)SDS in this situation? Sigma or the garage chemist? This goes back to my earlier concerns about the transfer of risk information as chemicals change hands...

It's interesting to note that only 2 of the 3 GHS information sources cited by the PubChem LCSS
https://pubchem.ncbi.nlm.nih.gov/compound/11645#datasheet=LCSS&section=GHS-Classification&fullscreen=true
include the flammable hazard for dimethyl mercury, although the flashpoint is clearly 4 degees C according to Wikipedia as well as commercial sources.

- Ralph

Ralph Stuart, CIH, CCHO
ralph**At_Symbol_Here**rstuartcih.org

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