When I first got into my classroom last summer, THIS is what I found in my chemical storeroom...
So that was the nightmare I had to deal with. The broken bottle above turned out to be zinc oxide which is non-toxic but can be a lung irritant if inhaled (such as you might get if you were to sweep it up). It expands when wet which is what caused the bottle to break. It took several months and a visit from our insurance inspector before someone who was respirator trained finally cleaned it up.
There was also no inventory from within the last ten years. The most recently dated chemicals were purchased in 2010. Trying to find what I wanted to use was a nightmare because I was told that the previous teachers followed the Flinn organization system (which is very good and what I am NOW using) but when I went to look for things where they belonged, I didn't find them, nor did I find them where the cabinet labels said they should be. Whoever was using the chemicals before me (obviously not the person who had been there for the last three years) apparently didn't pay much attention to where they put things away.
So when I finally got some time, I started taking an inventory of the chemicals that we had. I removed several for disposal due to age (or apparent age as most of them didn't have purchase dates) and put in a request to spend the money to properly dispose of them following EPA and state regulations. I also decided to rearrange the storage area to better accommodate the items we have more of (such as nitrates) rather than having a lot of space for things we don't have (such as most organics).
After much pain and suffering and entering into a spreadsheet, I finally have my school's storage area up to a standard that I can proudly say is "mine". I did end up using the Flinn storage plan, but with a few more shelves dedicated to certain things than others. I also like to have the Flinn catalog (you have to request it to get the whole thing) handy for a list of proper disposal techniques for pretty much every chemical someone might have.