You want “food grade” diatomaceous, which is reasonably safe. Personally I wouldn’t use it preemptively, only when there’s a suspected problem. I would wear a mask when applying.

“Pool grade” diatomaceous earth should not be used, it is hazardous to be around as it’s structure was changed by heating.

https://www.diatomaceousearth.com/blogs/learning-center/begi...

It's generally considered safe. It's sold as an additive to livestock feed, though I don't know what the purpose there is.

It's very finely ground volcanic rock. The particulates have very sharp edges which shred insect exoskeletons. It doesn't hurt your skin though.

It might cause a problem if inhaled, similar to silicosis but that's mostly a guess.

Some people leave a line of it on windowsills or door thresholds to keep bugs out, but it's a fine powder that gets everywhere and makes a mess. Personally I wouldn't leave it around but that's up to you

> It's very finely ground volcanic rock.

No. "Diatomaceous earth is made from the fossilized remains of tiny, aquatic organisms called diatoms. Their skeletons are made of a natural substance called silica." http://npic.orst.edu/factsheets/degen.html

> It's generally considered safe. It's sold as an additive to livestock feed, though I don't know what the purpose there is.

Antiparasitic.

> It's very finely ground volcanic rock.

Wikipedia is pretty clear that it's finely ground fossils. (It also says that it's sedimentary rock, as is necessary for fossils. Fossils can't be volcanic rock; their structure would be destroyed by melting.)

They also aren’t necessarily ground (the fossils) - and are made of silica.

Breathing it for long periods of time wouldn’t be ideal.

I'm going to go ahead and suggest you don't make a proclamation of safety (about a product associated with severe lung disease) followed immediately by "mostly a guess".