Debka often has some elements of truth in their reports, but I have to agree with you on this one.
I don't doubt that he's built underground facilities, and he may well have them in tunnels. But no real defector on the run from Hussein is going to give an interview to Debka--or any other journalist/news person, etc.
It's possible that Debka came by this bit of intelligence and made the interview up to cover their source.
I've heard before that after the inspectors were kicked out before, he began building new facilities underground beneath the old ones.