Just to clear this up: Silicosis is the province of "Pool Grade" DE (~20% Crystalline Silicon Dioxide). One can easily make the distinction between ADE & calcined DE by placing a small amount on the palm of one's hand on a sunny day and, if it glitters and glints it's the calcined product (melted into "glass" and crushed into tiny shards - yes, exposure to this can result in Silicosis - most often diagnosed in workers lacking adequate protective gear at calcined DE manufacturing facilities).. ADE, on the other hand, remains a dull gray flour. ADE is regarded by both the FDA & EPA as GRAS (Generally Regarded As Safe) and is approved for indoor use (under kitchen cabinets/in the beds of dogs, etc) as an insecticide.
Now, where things get interesting is that when sold as an "insecticide" for indoor use it falls under the EPA's Pesticide labeling requirements. Producers/Manufacturers use this as an excuse to jack the price. So, I buy a 50 lb. bag at the feedstore for $25 while on a back shelf in the same feedstore is a 2 lb. bag of the very same ADE selling for $8.95 ("for the homeowner"). EPA had to send out a series of nastygrams to the biggest producer/manufacturer, Celite Co., to remove "For Commercial Use Only" from any quantity as "this product can be used by homeowners, as well". Celite was busy creating a "line" of products - with different price points - from the same ADE, e.g., a 50 lb. bag of ADE being $25 (Canton Mills), while a 50 lb. bag of Celite's Diafil 610 (nothing but ADE) went for $27 - nick the cattle producers as well.
To be certain, regardless of which materials one employs in the coop/shed THERE WILL BE DUST. Any member with sufficient concerns about, or already existing problems with, lung function/compromised immune response should, at the very least, be employing an N-95 rated mask when in the coop/shed.
) and bright-eyed this morning (swear by Estes Hatchery line of Black Sex Link hens). Only "exposures" of dust I concern myself with? Yeah, upwind is good. 
