Think that some of the Airbus aircraft have a O2 mask deployment switch on the FAP.

Aerotoxic sickness

Been a known problem for years over in Europe

Don't deploy them in smoke/fire scenarios.

Once they drop, kind of forced to use them because the O2 generators get so hot and will smell like they are burning. To use them in a smoke environment it would be hard to convince the passengers to use them correctly, as in...for smoke. The flight attendants say every brief that O2 is being delivered even if the bag is not inflated. This is for loss of pressurization as the deflated bag is giving mix of O2 and ambient air. If they could calm their breathing and inhale only each time the bag inflates, then there is no ambient air, and thus great for smoke. If at any time smoke or fumes becomes the greatest threat, smoke removal should be performed, and that would be quicker than trying to reteach the passengers how to use the mask in a different way than they were briefed.

NO! NO! A thousand times NO! Passenger oxygen masks are not sealed. They mix the provided oxygen with cabin air. So if you deploy oxygen masks only for smoke, YOU are encouraging them to breath more smoke into their lungs adding to the possibility they will die from smoke inhalation.

Obviously, when the masks come down, most of the passengers will start anxiety breathing and take MORE air into their lungs than when they are relaxed. So giving them the masks exacerbates the problem of smoke inhalation.

Don't believe me? Next time you fly, go get the demo kit, put the mask on and see if you can still breath. If you're getting air with the demo mask on, your passengers will get smoke if you deploy the masks for that reason.

Passenger oxygen is for depressurization or medical requirements ONLY. Period.

It still amazes me how many professional pilots haven't figured this out.

Exactly. Not seconding guessing the CA...however, perhaps a better solution would be a quick call to the Lead FA, telling them "masks wont be deployed, hand out as many wet paper towels you can or bottles of water to wet clothes to place over face to breath."

If nothing else, important to ask "what would I have done" because you never know

You guys are assuming they dropped them for smoke. The Removal of Smoke QRH states to set the landing elevation to 10,000 or MEA/MORA, whichever is higher. Their case was probably higher. My heart goes out to the gentlemen that died in an O2 rich environment in the NASA tragedy, but I have a feeling that the flow rate of a O2 generator would not significantly change the O2 environment in a passenger cabin, especially if it isn't even strong enough to fill the bag with normal respiration. If one had one hand, they could flex the muscles that would apply pressure on the mask to help form a seal, but then they'd still get ambient air if they didn't wait for the bag to fill. Nobody is advocating to drop the masks for smoke, but if they dropped when I was in the passenger cabin and the thing was full of smoke, that's how I'd use it.