Are Crayons Included in One of the Food Groups?

I have been working on coloring with Landon, but until recently all he would want to do was eat them. So, I would put them up and try again later. This week he finally started coloring and not eating the crayons, or so I thought. He waited until I got comfortable enough to leave him unattended for like a second, and then the next the I know, Landon has a blue mouth. Good thing, crayola is non-toxic.