Quote:
There definitely
IS A DIFFERENCE, safety-wise. That some people aren't aware of it doesn't mean it doesn't exist
The non food grade DE (sold for pool filters, agricultural use, etc) is made from marine diatom deposits and contains very very sharp silica crystals which are Not Good For You if inhaled.
http://www.jtbaker.com/msds/englishhtml/d1288.htm
It can cause silicosis, a permanent irreversible lung disease. Most cases of silicosis are from people with significant ongoing occupational exposure, but it can also occur from much milder and shorter exposures too. Its effects are not immediate, meaning that it's not like you're going to use pool grade DE one day and be hacking your lungs out the next... so you may not even KNOW that your problems, or your animals' problems, trace back to pool filter DE. Hence some people saying 'oh don't worry'.
http://en.wikipedia.org/wiki/Silicosis
The food grade DE, which is what you oughta be using, has most of its silica in 'amorphous' form rather than long sharp crystals. It still whacks arthropods that come in contact with it, but while it is no better for you than breathing any other kind of dust it is also no *worse* for you than breathing any other kind of dust. I am not aware that there is any risk of silicosis from the food grade (that is *why* it can be labelled 'food grade' of course!).
If your health and that of your animals is worth saving thirty bucks, fine, but don't say you weren't warned
Pat