LED T-8 Replacements - Not for Emergency Exit Fixtures

I've replaced all my fixtures with LED T-8 retrofits to avoid replacing the bulbs so often.

Over the past few years I don't ever recall seeing this notice:

"Not intended for Emergency Exit Fixtures"

And now many of the retro fit bulbs are showing up with this notice, but I don't see any explanation.

Are these fixtures somehow wired differently so that retro fit is a problem? Or is there some other issue? I would have thought that any replacement that would use less energy would allow the emergency lighting to last longer and therefore be a good thing.

What's the issue?

Thanks much,
wp

Emergency lights are constant hot lights. They have a battery backup or other constant power source that keeps them on even when the power is cut off. Those bulbs have an issue with arching at the tombstones and catching fire if they are installed while the power is on. Read the instructions on the bulbs. You must turn off the power before inserting the bulbs. Obviously, you can't do this with emergency lights, so that's why they say not to use them in emergency fixtures.