I was using thiophenol for the first time the other day, for a nosyl deprotection. I've heard all about it before, particularly how bad it smells, and it's appeared on Derek Lowe's blog because of this.
At first I'd done well. I'd contained it in my fumehood, doing all the work with the sash right down, just in case. Capped the bottle, put it back in the vented cupboard. Easy, I thought, can't smell a thing, what's all this fuss about?
Then I came to rinse out the pipette I'd used to transfer the thiophenol. I'd left it in my fumehood to clean at a later date so as to not stink up the sinks, but I left it long enough for me to forget what was in it. When I came to clean it I knew it would have been used for something reasonably nasty, since I'd left it in my hood. The only thing I could remember using a graduated pipette for recently was thionyl chloride, so I thought, a bit eggy and a bit vinegary, no trouble.
I started rinsing and I immediately realised that it was not thionyl chloride, and was surrounded by the stench of burning tyres, so much so that it made me feel more than a little nauseous.
All from rinsing a pipette that had been used for 0.5 mL of the stuff.
I now rinse all my pipettes immediately after use. Lesson learned.