Most people have been conditioned to fear chemicals, but the typical fear is not consistent with the actual risk. The vast majority of chemicals that are encountered in everyday life are quite safe. But, when your profession is chemistry, that changes fast. Here is one example.
Being an organic chemist is kind of cool. We are trained to convert one chemical substance to another by using the appropriate reagents (chemicals or catalysts that cause a chemical reaction).
"Appropriate" covers a wide range of chemical substances, some of them benign, like sodium bicarbonate or acetone, and some of them that are just the opposite(1). But, sometimes you just have to suck it up and use something nasty. And, there's nasty, and there is nasty.
Here is one that is nasty. It's called tert-butyllithium, aka t-butyllithium. Most of us have used it. Few of us have enjoyed doing so.
A shortened version of a YouTube video. Original link: https://www.youtube.com/watch?v=7aJitlPFWOs
Yes, it is so reactive that it ignites in air (pyrophoric), and even more so with water, so whenever you handle it, precautions must be taken to ensure that it comes into contact with either.
The stuff comes in a bottle with an air-tight rubber seal, and it must be removed by syringe, and then transferred to a flask that has been flushed with an inert gas like nitrogen or argon to get rid of any traces of oxygen.
Withdrawing the liquid is the most dangerous part of the process. This was the cause of a horrible accident that happened at UCLA in 2008, in which a research assistant died from the burns she suffered after spilling the liquid on her clothing, which then ignited.
To follow: Something far worse — dimethylmercury.
(1) Chemistry blogger Derek Lowe has written a number of times about "Things I Won't Work With." It is both entertaining and informative. The things he won't work with are far worse than butyllithium, which should technically be listed under "things I really don't want to work with."