What keeps this from being certified for playgrounds?

My training in Pesticide Management revealed "Residential areas, playgrounds and areas near streams are considered a -Sensitive Area-." Because all pesticides have a warning on the label about -Hazards to Humans and Domestic Animals-, no pesticide will be certified as safe for your children to play in a treated area. "Diatomaceous Earth" is safe for human consumption and very devastating to insects. This is the base ingredient in Seven Dust and other home use insecticides, even some products used in food processing.

Don't know, but it is dyed and has large chunks of wood that could cause splinters.