In , M Traveler wrote:

SNIP

I had a problem that wasn't exactly like that. I had a CF bulb in a
socket where the bulb was horizontal, and always on, in the utility
room. When I got home it was melting and sparking. Fortunately the
floor was cement so no fire started.

Can you tell us what brand and model? Or even what brand?

I have known a few dollar store stool specimens (mostly not UL listed)
to do scary things, but I have yet to see anywhere a major brand CFL do
that or show signs of having done that.

BTW - I only see UL logo on light bulbs with built-in ballasts.

- Don Klipstein )