Originally Posted by
ethicalconundrum
(Oh - in case you didn't know, there are duplicate guarded switches for manual deployment of the O2 on ALL airliners built since 1998)
Could you point out in the photo you supplied where the ‘duplicate’ switches are?
The Manual switch is the backup for the ‘Automatic Deployment’ function in the event of loss of cabin pressure.
Oxygen masks are NOT deployed for fire/smoke events. The masks do not seal and allow ambient air to circulate within.