How terrible. In my high school (in NYC) we were never able to use the chemistry lab during my time there because at the beginning of the term, somebody had not only caused an explosion but somehow contaminated the entire space. I’m not sure with what, but the room was locked and off limits. Nobody was killed or injured in that one, at least.
Of course, this was NYC in the 1960s, famous for its schools with peeling paint and leaking roofs, so they probably just didn’t want to spend the money to fix it.
In my HS Chemistry class, the teacher demonstrated that potassium explodes in water. After the explosion the purplish- looking cloud set off the fire alarms. The buildings had to be evacuated and the FD called in.