I think the worst you can expect is that the colors will be a bit off.

What a waste. Film is not milk. Except for the very high speed film such
as T-Max P3200, most film does not "go bad". It ages. All films are sensitive
to cosmic radiation, but until they get to the speed of P3200, they are
not sensitive enough to matter.

All film develops fog with age, although it takes many years for normal
speed film to become a problem. Color film experiences two problems,
one, it becomes obsolete and the processing becomes difficult or in
some cases impossible to find. Kodachrome is unfortunately headed that
way. In the case of slightly out of date Ektachrome, there is no chance
of that for a long time.

The second is color shifts. Professional color film is aged in caves until
it reaches the desired color response and then shipped with short expiration
dates under refrigeration. This is because professional photographers care
about exact color balance and need the consistency.

Consumer film is just shipped as needed, the color shifts won't bother
your average consumer.

Unless your film was stored in an oven (you said it was refigerated),
it should be fine for several years.

As others of have said, it probably should not be used for those once in
a lifetime shots, but if you happen upon one with that film in your camera,
I would not hesitate to use it. YMMV.

If you really don't want to use it, and want to do a "good deed" stick it
in an envelope and send it to me. :-)

Geoff.

Last week I saw work by an excellent slide worker who *only* uses out of
date Kodachrome 64. He called new stock, rubbish.

Simon

Don't worry about it.  Been there, done that.  Works fine.  If you're
doing color critical work for a customer, then no.