I mentioned this to Ralph offline since I thought it a bit off-topic, but Monona's post makes it relevant. One thing we need to be inculcating in students is the difference between incidental contact and immersion/frequent contact applications of gloves.
I know of an incident that involved researchers (accidentally) spraying acetonitrile solution on their K-C Purple Nitrile gloves instead of 70% ethanol. Fortunately, acetonitrile is volatile and it was determined that the gloves would stay wet
for a minute or less, during which K-C's penetration data indicated a dose in the tens of picograms range. If they'd been dipping their hands in the mixture or washing handheld microscope slides for a half-hour or something, there would have been the potential
for a much larger dose. Similarly, if Karen Wetterhahn had immediately removed her latex gloves instead of finishing her work first, she might have avoided her lethal dose of dimethylmercury.
I think it's important that students understand that the application/expected contact time affects the choice of suitable gloves. If you can expect very short contact time (and the penetration time isn't near-instant), AND your application is
such that you'll actually notice the exposure, the Purple Nitrile gloves are suitable even for some chemicals that are colored red on the K-C chart. It's kind of a complicated topic, though, so I don't see it being related in a video. Having a full understanding
of the issues involved in this might, as a side effect, encourage researchers to design their experiments to minimize the potential for hand contact (holding the slides with forceps to keep the hands out of the rinse solvent stream, etc.)
(In the incident mentioned, there was of course a potential for inhalation exposure; fortunately, the spray was carried out in a ventilation stream right in front of a BSC, in a direction away from the researcher's breathing zone, so that was
minimal.)
regards,
dan
=============================
Dr. Daniel R. Kuespert
Homewood Laboratory Safety Advocate
Krieger School of Arts & Sciences/Whiting School of Engineering
The Johns Hopkins University
103G Shaffer Hall
3400 North Charles St.
Baltimore, MD 21218
(410) 516-5525
In the first student video, why not simply say that both methanol and methylene chloride are capable of penetrating these thin nitrile Kimberly Clark gloves in under a minute? And that
if users are interested they can use the chart to see the rate at which the solvent is passed through the glove? And why not actually use Kimberly Clarks' recommendation that gloves be immediately removed if there is an incidental splash of the chemicals on
the glove?
Monona Rossol, M.S., M.F.A., Industrial Hygienist
President: Arts, Crafts & Theater Safety, Inc.
Safety Officer: Local USA829, IATSE
181 Thompson St., #23
New York, NY 10012 212-777-0062
