I grew up in little town on the Central Coast of California called Lompoc. Lompoc has one of the highest deposits of DE in the world. Some of the hills look like they have deposits of snow. We played in and around it, and when the wind blew the right direction, the dust tailings from the mines would cover our cars and plants (no aphids on moms roses!). Many of my friends and their parents and grandparents are still there, alive and well. I don't remember any reports of health problems or cancer clusters, and I never had dry skin or abrasions. Even with that personal testimony I would not over expose myself to any dust. But DE is great stuff. Google "diatoms" and click on Images to see what the little creatures look like magnafied...little complex glass sculpures!
From eHow.com:
"Know what DE will kill and won't kill and how it works. When considering DE as a pest control product, it can be safely used around all types of animals and is only deadly for pests like insects. It is not harmful to earthworms. Among the list of pests that it kills and repels are: ants, termites, slugs, snails, fleas, fly maggots, aphids. bed bugs, mites, ticks, roaches, earwigs, scorpions, cutworms, ear worms, lawn grubs, grass hoppers, and many more. It does not kill due to a chemical action like most toxic poisons but rather kills by the structure of its sharp microscopic edges. The hard bodies of the pests are sliced open by the material and it literally drys them out and they die. Complete insect control may take several days as the insects die off, but whereas chemical poisons act fast and have a short residual effect, diatomaceous earth, while working slower will remain active and nontoxic as long as it remains in the environment."
Read more: How to Use Diatomaceous Earth safely for Pest Control | eHow.com
http://www.ehow.com/how_5049476_use-earth-safely-pest-control.html#ixzz0t3fOrmD6
