This looks like some good stuff. I understand why the EPA would not like it, first they did not get there money to approve it, but more importantly it does look like a child would think it was chalk, and we all knew a kid in grade school that ate both chalk and paste (what ever happened to him?) and that could easily be deadly. So if you have children around, especially if you frequently have guests with children, I think it would be safe to say do not use or have around the boat! But if you are an adult and understand to not eat chalk, especially this chalk then you should be OK. I like the way it looks like it can be used in a very controlled fashion. But don't like that it looks like a child's toy.
To my idea looks like a use with caution product.
excuse me. I was one of the paste eaters, tasty stuff. Chalk is diatomaceous earth, why would anyone eat that? Paste was made from rendered animal parts hoofs and stuff. Do you think it may have effected me????