Diatoemaceous earth is safe if you don't breath a dust cloud of it. Any airborne silica is not good for you. Why OSHA now requires dust masks when scraping, grinding, or cutting concrete. It's common sense.
Silica is everywhere in nature, rubbing two quartz together will produce a small amount of air borne silica.
Silica is everywhere in nature, rubbing two quartz together will produce a small amount of air borne silica.