How does one know anything's "fine"? Your senses & accumulated evidence.
Let's say it's the Zombie Uprising of 2040, and I open a well-stored, individually-wrapped N95 mask from 20 years ago.
It's got no expiration date on it (as per the ones I bought last year), & it looks good, & doesn't give off any dust, & it smells the same as I recall new masks smelling. I'll figure that's "fine" – unless & until someone has specifically shared some study demonstrating their dangerous-yet-imperceptible degradation.
Is there such a study, or is this just "there be dragons" fear-of-the-unknown?
Let's say it's the Zombie Uprising of 2040, and I open a well-stored, individually-wrapped N95 mask from 20 years ago.
It's got no expiration date on it (as per the ones I bought last year), & it looks good, & doesn't give off any dust, & it smells the same as I recall new masks smelling. I'll figure that's "fine" – unless & until someone has specifically shared some study demonstrating their dangerous-yet-imperceptible degradation.
Is there such a study, or is this just "there be dragons" fear-of-the-unknown?