Originally Posted by
Basil
Perhaps that's because, in the hypobaric chamber, you start off with sea level air which may be more humid than that at high altitude.
I've never had a rapid decompression in an aircraft but there was misting in the hypoxia run.
In a actual aircraft explosive decompression if the aircraft is more then a few years old you will often get a lot of dust flying which will set off a particulate style detector.