Derik Lowe's in the pipeline has a bunch of stories from readers. Fun to hear about. The worst thing I've ever done is catch fire to the fume hood, that was in undergrad. No damage, but it was a near thing (considering the idiots left the flammable reagents all close together in a CARDBOARD BOX. The box caught on fire. Like I said, it was a near thing. I imagine the explosion would have seriously damaged me and possibly caught the building on fire. Yeah, that lab was pretty dangerous, looking back.

Since then i haven't worked much with really dangerous things. I once dropped a plate filled with 32P, i had to strip out of my clothes, change to scrubs, decontaminate the entire lab, and walk home in bare feet. 6 months later i got my shoes back. Humuliating, but not dangerous; and nothing was damaged (later i found out that 32P wasn't all that bad, despite some people's claims to the contrary).

Oh, okay, this almost takes the cake. I was assigned to refill the liquid nitrogen cell storage tank, along with another guy, for a few weeks. I forgot about it, he forgot about it, until someone noticed that all the liquid nitrogen was evaporated (well, mostly evaporated). I don't know what happened to the cells, they probably all died. Fortunately I left the lab soon after, and the cells weren't for our lab (another lab which occupied the same space).

The other liquid N2 story is more tragic, and happened to my current lab. Somebody was supposed to autoclave the racks that hold the boxes of cells of an EMPTY N2 tank. Instead, they autoclaved my PI's tank, destroying years of cells. That really hurt; we lost irreplacable cell lines and antibodies.