"Removing pants ("skinny jeans") that are tight at the ankles can be a struggle while dry, wet ones could be even more difficult to remove."

This potential scenario is the reason why skinny pants (tights, leggings, skinny jeans, yoga pants, etc.) were not allowed in my labs when we were using corrosives when I was teaching. The students complained and "tested limits" by showing up wearing them, but after refusing to let one student stay while dressed that way, I discovered that most who were "testing" those limits actually had other pants, loose fitting as required, in their bags, but were going to wait to see if I insisted on them following the rule. Most students, after that first confrontation in their lab section, kept a pair of scrubs in their bags and put them on over the skin tight pants for lab. That significantly reduced the likelihood of those skin tight pants holding the corrosive against the skin.

I also mandated crew neck shirts, no bare ankles and long sleeves when using corrosive chemicals. But for those, I could provide arm covers (these covered those bare ankles too) and a sweatshirt or jacket put on backwards to get the high neckline. I once had a female student who had had breast augmentation surgery, who always showed up wearing very low cut tops, which besides being distracting to many of the males in the class, left her expensive surgical work open to scarring if there should be a corrosive splashed or spilled. When I asked her why she was so willing to risk scarring there, it made the point, problem solved..

I also would discuss, in my safety lecture in week one of lab, and again each time we used concentrated corrosives (arbitrarily defined as above 3M acids or bases) the syndrome observed by medical professionals in patients who had experiences spilled corrosives and refused to remove all the clothing affected in the shower, which they call the bikini burn. That refers to the shape of the burns resulting from not removing underwear to get all the corrosive chemical off, and is a negative of the burn one gets in the sun while wearing a bikini, which is on the uncovered skin. This burn occurs on the covered skin, since the clothing holds the corrosive on the skin. I'd ask how many of them would like a burn in all the places their underwear covered. That would be a resounding "not me" or "no way", and we had had shower curtains installed around the showers, so I could also point out that we would do what we could to preserve modesty, but not at the expense of worst burning.

And, rather than pour acid onto my skin to make the point, I would do the Flinn Scientific Acid in the Eye Demo, each semester in the first week's safety lecture. In this demo, one draws an eye with a sharpie on each side of a disposable petri dish, separates two eggs and places the whites in the dishes, and then with the dishes under the document reader or on an overhead projector, adds a few drops of conc sulfuric to one dish, and count the seconds to the egg white going opaque where the acid landed (less than 4 seconds) and in the other dish, several dropperfuls of leftover 30% NaOH from a previous semesters saponification. Then I mix that one with a gloved hand, and the egg white becomes solid, although still clear. Within a few minutes it is as solid as Jello-Jigglers. This demo makes the point of the dangers without breaking any safely rules (like not pouring conc acid on one's skin purposefully), and it can be used to remind the students of the effects throughout the semester. It also makes the point that the safety shower and eye wash are not enough by themselves, since no one could get to them in under 4 seconds, so would be burned or blinded. They are shocked by that, and then I ask them to notice anything else that I am doing to stay safe, and of course, there's splash guard safety goggles, acid/base resistant gloves, and the lab coat I am wearing.

I like this lesson, and repeated it often, because it doesn't try to over-simplify staying safe. It makes the point that there are several components to staying safe in the lab, and all need to be followed to achieve that goal.. Also, I'd stress that the students were not expected to be the experts here, so the final component to their safety was asking for help in those situations. And I'd tell a story about breaking a glass of orange juice in the kitchen or breaking a beaker of acid in the lab. They would almost always guess that both should be cleaned up the same way, but of course they shouldn't. So, I'd explain that just mopping up the acid and sweeping up the glass and throwing them both into the trash would be a bad choice, since the acid can ignite the paper and the glass may cut someone with chemical in the cut. So, it makes the point that they should ask for help.

I found that explaining the whys for each rule, and then being hard-nosed about sticking to the rules, and re-emphasizing each time that it was for their safety, and that safety had to trump fashion worked. I'd have a run in every semester in each lab, with one student, but if I stuck to my guns, they generally backed down and miraculously discovered they actually had appropriate clothing with them. I had students every semester who wrote on evaluations that they had started out afraid of chemicals in lab, but learned that Meg wouldn=E2=80™t let them do things that greatly increased the danger in the event of an accident, so they felt able to relax and enjoy the lab. I never once in 17 years had anyone write on an evaluation that they thought the rules for safe attire were ridiculous or pointless. All who commented did so to praise me for keeping them safe. (and we never did have to use a shower, and only I ever used the eyewash, after doing something incredibly stupid, which thankfully did not result in injury to me - the eyewash worked.)

These practices made my job easier in the lab, too. The student would understand that the I was sticking to these rules to keep them safe, and that allowed them to relax and enjoy the experience in lab, which also means they learned better. Who can learn when they are so tense with fear of getting hurt? It made the lab more fun for me too, since relaxed students are better able to cope in lab.

Meg Osterby

megosterby**At_Symbol_Here**gmail.com
"It's better to be careful 100 times than to be killed once." Mark Twain

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