When I was 15 I wanted to make a snow scene on my HO layout. It was in the garage, and I figured I could use this somewhat off color white powder I found by the lawnmower. When I showed my mom, she asked what I used, and I pointed to the big brown bag. She freaked! "That's Limestone used for fertilizer"! I had to call the poison control center who told me to open the windows, use a mask and get vacuum up every speck of dust! Needless to say, I haven't modeled winter since.