I'm pretty lucky in that I have very few of them, and they tend to be minor. Oddly, however, the worst lab accidents have always been doing mundane things. The things that can really go awry are usually surrounded by a lot of care and multiple layers of safety and protection, so if things go wrong it's not too bad. Messy, but not damaging.
The few accidents I have had that involved personal injury typically come from things I really didn't expect, and therefore I wasn't watching like the paranoid neurotic I typically am. Quite a while ago I was doing a liquid liquid extraction and, since I wear glasses anyway, I wasn't wearing safety glasses. A lone drop flew off the drip tip of the funnel and arced perfectly over my glasses into my eye. I don't remember what was exactly in the funnel at the time, but it was probably the usual mix of aqueous mineral acid and product mixture in organic solvent. I do remember that it was so stunningly painful that it took specific effort on my part to maintain my grip on the funnel, and keep my hands and arms from involuntarily relaxing and dropping it.
My eye picked up a slight yellow tint for the rest of the day, and shortly thereafter I grew some small bumps on my lower eyelid in a cluster. I don't know if they came from that incident or not, but they were an almost daily reminder of it for about 10 years until they grew out and fell off earlier this year.
In grad school, on two separate occasions, I was putting the cap on an NMR tube, and the tube broke directly between the two sets of fingers holding the tube and cap respectively. Both times I accidentally pushed the shards into either hand. The first time it was about 2 am, and I wanted to get one last NMR in before I left. I was bleeding so bad from one of the cuts I couldn't really do anything but hold a paper towel on it, and there was no one left in the lab, or on my floor that I could find. I had to sit there like an idiot until it stopped bleeding sufficiently that I could tape it shut with label tape. We were, of course, out of band aids. When I got home much later, after cleaning up the mess I had made, I changed the tape out for a bandage. It was interesting/gross to see that I had cut a question mark shaped hole as the tube attempted to get a core sample, and it was a challenge to remove the tape off without the flap peeling up and separating from the fat and collagen layers. I now throw out severely chipped and cracked NMR tubes, and put the caps on very very carefully.
Earlier this week I was getting ready to go home for the night, and was shutting everything down at my hood and bench. I kneeled, turned off my pump, and raised the trap out of the dry ice/acetone filled dewar. The dewar tipped over and poured its contents down the front of my shin and into my shoe. I was happy to see it hadn't broken and sent glass flying while deafening me, while at the same time I was stomping and shaking my shoe to remove the acetone from around my ankle. Oddly, and thankfully, there was little damage. My sock did soak up quite a bit in the front and freeze, unfortunately. An immediate survey showed the damage was minor, I finished shutting down and split. When I got home, I figured I would photograph it for fun. I have a great series of a fluid filled, swollen, and highly colored ankle healing from hitting my shin a few years ago, you just never know when this stuff will come in handy.
I apologize for the shitty pictures. Apparently my recently replaced phone had a protective film covering the INSIDE of the lens cover that I was unaware of until today.
The night of the "incident"
As you can't really see, the affected area is reddened and swollen pretty evenly. There is already a bit of ridging where the elastic of the sock was. It felt a lot like a reasonably bad sunburn.
Several days later:
Most of the swelling and redness are gone except in the most burned part. Doesn't hurt anymore except for when direct pressure is applied. Usually on accident, and is quite a surprise.
Look at how clear that is when you remove that little piece of fucking plastic! The color is somewhat unpleasant looking, but it feels fine, and is healing well.
Interestingly, a few days ago the same thing happened, and without any surprise or real thought my knee shot forward to catch the dewar and balance it until I had a hand free to right it. I think perhaps it's time to reevaluate my pump trap system.