Which is a bit specific. Now I didn't remember how to read the hazards directly off this form, because I'm more familiar with the generic form:

which explains that whatever the truck is carrying can react somewhat with other chemicals, and can cause a significant health issue.

Never one to pass up an educational opportunity, I had the kids look up that particular hazamat number, to find out its Calcium Hypochlorite. Now I know what Calcium Choride is, its a salt (CaCl₂). You can use it for ice melt because it will reduce the freezing temperature of water down below -40° and I also use it in my pool to increase the hardness. Its one of like eight crazy things you have to keep track of in order to have your water neutral so it won't start dissolving the walls of the pool or leaving scale on the ladders. The crazy thing is if you buy it from the pool supply store in their fancy packaging, you'll pay $3-5/pound, but if you just by the pro-ice melt which is 100% the same thing, its fifty cents a pound.

Anyways, Calcium Hypochlorite has some oxygen mixed in, so its Ca(ClO)₂, and it turns out you could add it to the pool to increase the calcium as well, while getting lots of free Chlorine for sanitizing. Its a regular ingredient in pool shock, which luckily I never have to use. I have a salt pool, which has an electrolyzer which constantly splits the salt into sodium and chlorine, and its a beautiful thing. While the neighbor has to check and add Chlorine to his pool a couple of times a week, this thing runs for weeks at a time unattended.

But usually you don't use a huge amount of Calcium Hypochlorite, because the calcium will build up and make the water hard. However its good in water treatment plants, where the water is eventually consumed and replaced with new stock from underground or lakes or wherever. So now I know, now my kids know; and I can move onto wondering about the next thing that wanders by.