In article , Bill wrote:
It is a heat/fire/safety issue.

Too much heat and no ventilation can cause a lot of heat build-up above the
fixture. Place insulation above the fixture in the attic and it can get
worse! I've seen old wiring above these fixtures where the insulation has
cracked from the heat and there are bare wires in the box above the fixture.

So potential shock hazard and/or fire hazard. How about using a compact
fluorescent which is more cool and also saves energy?

CFLs generally don't take heat as well as incandescents, and many will
cook themselves to death in this fixture. (Enclosed bathroom ceiling
fixture) I would use only ones rated for recessed ceiling fixtures. The
highest output one of these that I know of if the Philips SLS 23-watt
non-dimmable. (The dimmable one was not rated for recessed ceiling
fixtures last time I checked.)

- Don Klipstein )