By "WORM" do you mean a normal writeable CD, or the special WORM drives which were "about to take over the world" about 10 years ago and are now long obsolete except in very special applications requiring evidence to be preserved?
I reckon writeable CDs should last a very long time but they do suffer from humidity and temperature, especially both together. Environmental control (achieving something like a normal summer office atmosphere) appears essential.
Everybody loathes mag tape, but it has always been way ahead of any other removable medium when it comes to capacity. I haven't heard of pro grade data tapes (DDS or DLT) delaminating. Maybe you mean normal audio tape? I would expect audio recordings to be useless after say 20 years anyway, due to loss of magnetisation (making the S/N ratio poor) and things like print-through.