Chemists routinely consult material safety data sheets compiled by chemical manufacturer and suppliers for information about protections against specific chemicals. Three material safety data sheets (MSDS) were available for dimethylmercury. Alfa Aesar, the chemical supplier from whom Wetterhahn bought the dimethylmercury, recommended "rubber gloves." Organometallics, the company that manufactured the dimethylmercury, recommended gloves made of the synthetic rubber neoprene. Sigma Aldrich, the chemical supplier that produced the third MSDS, recommended wearing "chemically impervious gloves." However, "there is no such thing," says the College's health and safety director, Michael Blayney. "No glove is completely impermeable." The rates of permeability vary according to the glove type and the chemical involved. Despite the recommendations on the material safety data sheets, Blayney says, no one had actually tested any kind of protective gloves to see how they stood up to dimethylmercury.
>And wondering about Karen's gloves, were they standard dry-box gloves or did she double glove them inside of the glove-box with another type of glove, as we sometimes double glove with our disposable tactile gloves.
I believe that Dr. Wetterhahn was working in a fume hood rather than a glove box on the occasion of her mercury exposure. I assume that she was using the fume hood to control the fire hazard associated with the dimethyl mercury (flashpoint = 5 degrees C), but the fume hood does not add value with regard to dermal toxicity hazards; and latex gloves add minimial protective value as well. OSHA reports that the dexterity value of the latex gloves led to that choice. I believe that the OSHA presentation on this event suggested that Silvershield gloves were the only appropriate choice at that time.
One of the learning points I take from this story is the challenge of working with chemicals that present multiple hazards while balancing chemical and human factors.
- Ralph
Ralph Stuart, CIH, CCHO
ralph**At_Symbol_Here**rstuartcih.org
---
For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org
Follow us on Twitter **At_Symbol_Here**acsdchas
Previous post | Top of Page | Next post