Missing in the DE discussion is the issue of grade or quality of material. Calcined DE, which has been heated, is typically worthless as an insectide (or other pest control) and is much more hazardous to inhale, as the calcining process rounds off the sharp points and changes most of the silica from amorphous to crystalline, which is the carcinogenic form of silica.
see www.biconet.com/crawlers/infosheets/DiaEarthPestCtrl.pdf http://www.safe2use.com/safe-products/diatomaceous/diatomaceous_Earth.htm http://www.eap.mcgill.ca/Publications/eap4.htm " The only health precautions that need to be taken are that if large areas are being treated with a power duster, the applicator should wear a mask to prevent inhalation. Because DE is made of silica, people sometimes mistakenly think that DE causes silicosis. As indicated above, however, pesticide quality DE is usually over 97 per cent amorphous silica, which does not cause silicosis, which is associated only with crystalline silica. Indeed, inhalation of road dust and grain dust IS likely to be more harmful than DE. " http://www.cdc.gov/niosh/pel88/68855-54.html So be sure, if you do use DE, that you have the right stuff. And, don't inhale excess dust if you can help it. Of any kind. Frank Teuton <Previous post deleted to insure personal security, happiness, prosperity, and free breathing...;-) >
