Here's one thing from when I did undergraduate research:

I expected grad students to know what they are doing and practice safety. I worked in a lab that had a powerful UV light that we kept off to the side under a cardboard box. The light was used to accelerate curing of UV activated glue. The light was powerful enough to basically give you the equivalent of a sunburn to your eyes if you even glanced at it. When we used the light, we made sure to announce its use and cover it up before plugging it back in. One student in our lab moved the lamp to the middle of the room and turned it on as I was walking through the room right in front of my face. I said "I saw that" and he shook it off as if it were nothing. It was definitely not nothing. Within about 8 hours, I was essentially blind because my eyes were now much more sensitive to light. I spent about two days effectively blind. I don't recall discussing this with the professor I was working under, but it did help me decide to stop working for that professor. I should have discussed this with them. Thankfully, there was no lasting damage to my vision. At this point I use all PPE available, and am a stickler when it comes to safety. Worse, my work is now entirely computational!