When I was working in a lab I had to work with liquids that were radioactive, which wasnt dangerous like big explosions, but if I had accidentally swallowed it I would be in quite a bit of trouble as that causes cancer and radiation poisoning. We had to do everything behind a lead-shield and wear lab coats and safety glasses and face masks.
Radioactivity, the same as Wei. Its low level radioactivity but its still dangerous. Once someone spilt some radioactive liquid, and the lab had to be shut for 6 months until it had all degraded naturally!
We are planning some experiments with radioactive metals the moment and there are loads of procedures put in place to make sure it is safe to use them. We have some dangerous chemicals in our lab but everyone know how to use them safely and what to do if there ever was an accident.
The wost accident I ever had was at school in a chemistry lesson when my teacher set my arm on fire – it was only for a second but it burnt all the hair off!
Working with liquid nitrogen is dangerous and definitely require gloves and goggles. Also ethidium bromide is a chemical that is often used by scientists but thought to lead to cancer, so has to be treated with care.