[Philsuma]

We all know it kills mites dead, so it would be very effective to place around your ff cxs...

But

Would breathing in the stirred up particles wreak havoc on yer lungs?

[joneill809]

http://npic.orst.edu/factsheets/degen.html#exposed

After inhalation of amorphous diatomaceous earth, it is rapidly eliminated from lung tissue. However, crystalline diatomaceous earth is much smaller, and it may accumulate in lung tissue and lymph nodes. Very low levels of crystalline diatomaceous earth may be found in pesticide products.

...Amorphous diatomaceous earth has not been associated with any cancers in people.

I keep my cultures in vented covered bins and generally I put them back in the same depression they were in which seems to minimize the dust. Every once in a while I gently fluff it back up but I'm pretty careful to not kick up a dust storm (I use the amorphous stuff).

[Philsuma]

Need to use 'food grade' Diatomaceous earth. Some people do actually eat it!

[Broseph]

I use food grade DE in my fruit fly incubator and with my springtails (not under the isopods). I use a VERY fine dust layer on the surface of the bottom- like dust on an old book shelf thin. A little residue still falls off the fruit fly containers when I tap flies out, but I have never had a mite issue. I've even left old dead cultures in there just to see... No problems!

Edit: So far I don't have any lung cancer- that I know of- and/or that could be definitively connected to DE inhalation...

[Sherman]

I say good and bad.
Clearly a good way to limit the motion of unwelcome little bugs.
Pretty bad if you repeatedly breathe it (for decades).

From Wikipedia:
Safety considerations[edit]
Inhalation of crystalline silica is harmful to the lungs, causing silicosis. Amorphous silica is considered to have low toxicity, but prolonged inhalation causes changes to the lungs.[22] Diatomaceous earth is mostly amorphous silica, but contains some crystalline silica, especially in the saltwater forms.[23] In a study of workers, those exposed to natural DE for over 5 years had no significant lung changes, while 40% of those exposed to the calcined form had developed pneumoconiosis.[24] Today's common D.E. formulations are safer to use as they are predominantly made up of amorphous silica and contain little or no crystalline silica.[25]

The crystalline silica content of D.E. is regulated in the United States by the Occupational Safety and Health Administration (OSHA), and there are guidelines for the maximum amounts allowable in the product (1%) and in the air near the breathing zone of workers (6 mg/m3).[25]

In the 1930s, long term occupational exposure among workers in the cristobalite D.E. industry who were exposed to high levels of airborne crystalline silica over decades were found to have an increased risk of silicosis.[26]

Today, workers are required to use respiratory-protection measures when concentrations of silica exceed allowable levels.

Diatomite produced for pool filters is treated with high heat (calcination) and a fluxing agent (soda ash), causing the formerly harmless amorphous silicon dioxide to assume its crystalline form.[25]

Being familiar with the pool version of this stuff, I am a little gun shy around it.
Sensible use should not cause a problem, just don't kick it up into the air.
...and I'm not eating any!

[Philsuma]

I wonder how well it works on New England cockroaches?