My cats had fleas so I used diatomaceous earth around the apartment. After vacuuming, a lot of dust filled the air but I opened all the doors to ventilate the air. After some hours the dust in the air went away for the most part. I cleaned everything up but there are still small areas here and there that need dusting or wiping. After cleaning I realized I used non food grade diatomaceous earth which I know is high in crystallized silica. I cleaned and vacuumed over and over and gave the cats baths to get any powder off of them. I put an air purifier and changed the air filter. I scheduled a vet visit to have the vet listen to their lungs. Should I be worried? Can this cause death in cats? My cats have been acting completely normal so far and this happened 2 days ago.

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    Just an fyi in case of need in the future: the tiniest particles are the ones which do the most damage, because they're the ones that can get deep into the lungs. Unless you're using a vacuum with a HEPA filter on it, vacuuming traps the larger particles and sends the much more dangerous ones back into the air for you to breathe in. One exposure is unlikely to do much damage, and if there is any damage, it will be in the distant future, not immediate. (You did everything else that could be done, but if you see any silica dust, try wiping it up with a damp cloth; that causes no harm at all.) Commented Dec 28, 2023 at 23:43
  • I actually found out that the DE I used is made out of amorphous silica rather than crystallized silica. Made me feel a little better.
    – user27137
    Commented Dec 29, 2023 at 23:41
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    "Food-grade" DE is safer than non-food grade because the particle sizes are larger, but it does contain small amounts crystalline silica. Non-food grade DE contains more crystalline silica than food grade. High (not one-time) exposure to amorphous silica can cause lung disease. All forms of silica (maybe with the exception of silica gel) should be used with some caution. Commented Dec 30, 2023 at 17:11

1 Answer 1


A one-time exposure should have limited effect, despite being something obviously to be avoided regardless. Quoting from section "safety considerations" on Wikipedia (emphasis mine):

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. Diatomaceous earth is mostly amorphous silica but contains some crystalline silica, especially in the saltwater forms. In a 1978 study of workers, those exposed to natural diatomaceous earth for over five years had no significant lung changes while 40% of those exposed to the calcined form had developed pneumoconiosis. Today's common diatomaceous earth formulations are safer to use, as they are predominantly made up of amorphous silica and contain little or no crystalline silica.


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

Note that the study considered exposure over a period of five years, and yet a good portion of the probands were unaffected.

Considering work safety regulations, or rather the lack thereof, in the 1930s, one would assume that "exposure over decades" in this context means more or less breathing in the stuff constantly. Still, suffering from silicosis after enduring this for an entire career apparently wasn't guaranteed, but the risk was considerable.

This would suggest that short-term exposure poses relatively little risk.

Nonetheless, care should always be taken when using anything in the household, chemicals or otherwise, with pets around.

Best practice we've been following is to thoroughly check possible health hazards for our pets, and if something isn't proven harmless, we are looking for alternatives.

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