For a long time (late elementary school through high school) I had a chemistry lab in the basement in North Liberty, and this sign is still there on the way down the stairs.

I only injured myself once. I had read that you can't ignite a sugar cube just by putting it in a flame, but if you rubbed the cube in ash first, it would burn just fine. It was a bad idea to hold the sugar cube in a spring-loaded clamp for the 2nd part of the experiment, when it burned just fine. And melted, and threw flaming liquified sugar through the air and onto my arm. Oops.

At the time, there was no running water in the basement, but there were 13 stairs, and I think I only used 5 of them. I have a small scar.