Two points related to that:
1. Glove permeability increases when the glove material is stretched, such as when the user chooses gloves which are too small. I routinely see large labs that have only “S” and/or “M” gloves on hand. I wouldn’t be surprised if that 1-minute permeation time for conc sulfuric is on the order of seconds if one is flexing the hand a lot or using a small glove. Couple that with the sweat on the hand inside the glove after using it for a while, and you have a recipe for a fairly large area of exposure.
2. One of the best ways to get skin contamination is to reuse gloves. I also routinely see used gloves on bench tops, obviously intended for further use. I generally tell students that if they do that, they’re going to contaminate their hands and/or their sample. For some reason, the latter argument seems to be more effective. The problem seems to be more widespread in students trained in labs that can’t afford an adequate supply of gloves (e.g., developing countries).
If there is photographic documentation of the injury that can be shared, I’d love to have a copy. While gross, it may communicate the hazards of misusing gloves well to users. Sometimes you just have to be graphic in order to get the point across.
Regards,
Dan
Daniel Reid Kuespert, PhD, CSP
11101 Wood Elves Way
Columbia, MD 21044
410-992-9709
Hey folks:
I think (based on what was reported) there is little possibility of permeation causing the problem. Thin nitrile gloves are not recommended for direct acid contact when they are 0.3mm or less. Further, iodoacetic acid has not been tested for permeation resistance to my knowledge, but nitrile is NOT recommended for acetic acid. Nevertheless, what is being described seems highly unlikely since it would effect more than the back of the hand.
There are three possibilities. Permeation (unlikely since the amounts would be very small), Penetration (more likely due to damage to the glove), or degradation (unlikely since the glove would visibly degrade).
Without knowing much of anything, I would say that it is not the gloves but the user. Somehow the person got some on their skin before putting on the gloves. Maybe cross contamination?
There are plenty of cases of gloves becoming contaminated on the inside for a variety of reasons and then the permeation is one direction (inward).
I would spend more time questioning exactly what took place and check for cross contamination.
Good luck on your quest for what was the root cause of the injury.
Zack
S.Z. Mansdorf, PhD, CIH, CSP, QEP
Consultant in EHS and Sustainability
7184 Via Palomar
Boca Raton, FL 33433
561-212-7288
Sue, So interesting. You said: " The assumption is that acid penetrated the gloves or fell off the gloves onto skin during removal." For either of these options to be true, the acid had to get on the gloves first. And that's where things went wrong: I propose:
STEP ONE: contact the manufacturer of the specific type of nitrile gloves that were used. That may not be your supplier. You want the actual manufacturer. No manufacturer approves of their thin mill gloves for chemical handling. But some of the companies like Kimberly Clark have chemical permeation charts.
STEP TWO: Talk to the technical people at the manufacturer about both chemicals that the student used. The technical people should not be defensive since they are clearly not liable for this injury. They never said these gloves should be used for prolonged contact with chemicals. Kimberly Clark has their policy right on their website which says:
Kimberly-Clark* Nitrile Gloves are thin gauge disposable gloves designed to provide
barrier protection and tactile sensitivity to the wearer. Our thin mil gloves are not designed
for applications involving prolonged, direct exposure to chemicals. Our intent in providing
this chemical compatibility information is to provide a guideline for use of our thin mil gloves in
applications where incidental splash exposure to various chemicals may occur. Gloves should be
removed and replaced immediately if incidental splash exposure occurs.
So if there was a splash or any contact between the chemicals and the glove, including on the back of the hand, the student should have known to immediately remove and replace the glove.
STEP THREE. If the permeation expert at the glove manufacturer thinks either of these chemicals can penetrate the thin mill gloves over time, this information belongs in the accident report. It establishes the most probable cause.
The Kimberly Clark chart says 98-95% sulfuric acid can go through the gloves in one minute. It is only after 47% dilution or greater that the full 8 hours of the ASTM F739 test can be attained. There is no data on the chart for iodoacetic acid. Ask the manufacturers about this one.
STEP FOUR. Rewrite policy regarding use of these gloves to exclude any more that a few seconds contact with chemicals. Use the manufacturer's policy language to protect liability.
STEP FIVE. Explain in student training that acids, solvents and other chemicals are molecules. The glove is just more molecules loosely strung together as a polymer. Many times the liquid molecules can squiggle right through the polymer membrane without showing any signs of having done so. The speed of penetration is related to the type of liquid, the type of polymer membrane, the thickness of the glove, whether the glove membrane was created from a water latex or solvent solution, and many more factors. This is too complicated to estimate so there is a nice ASTM test that manufacturers do that tells you how many minutes it takes.
Then hold up your glove charts. Nail the policy and glove charts to the lab wall and you're done.
-----Original Message-----
From: Wiediger, Susan <swiedig**At_Symbol_Here**SIUE.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Wed, Nov 6, 2019 12:04 pm
Subject: [DCHAS-L] delayed acid burn
Asking this question on behalf of a colleague from another university (so if there are follow-up questions, there may be a communications delay in answering them):
What kinds of delayed reactions are known for iodoacetic or concentrated sulfuric acid?
A graduate student was working with concentrated sulfuric acid to acidify wastewater (wastewater treatment plant effluent) samples, and spiking them with iodoacetic acid (small quantities, since it was a spike). An experienced student, who had done this before , she was wearing nitrile gloves (the typical disposable type). To the best of her knowledge, she had no skin contact with the chemicals she was using and used proper glove removal technique.
Approximately a day or so later, she noticed a blistered looking patch on the back of her hand, near the joint of the thumb and first finger bones – about the size of a nickel. It spread, and by about four days after the presumed exposure, covered approximately half of the back of the hand. On-campus medical referred to a more experienced doctor, who ended up referring the student to a hospital with burn expertise (including chemical burns). The campus EH&S felt the response was due to the sulfuric or maybe the iodoacetic acids; the hospital agreed it looked like a chemical burn. The assumption is that acid penetrated the gloves or fell off the gloves onto skin during removal.
Treatment ended up including cadaver skin transplant; the student seems to be recovering well and doing fine. However, all involved would like a better understanding of what might have happened.
Information related to the question above, or other ideas as to what else you might consider checking for possibilities, is welcomed.
___________________________________
Southern Illinois University Edwardsville
