Of course Tom Ridge denying it means NOTHING.
What's he gonna say? "Oh! Yeah! Sure we think OBL has snuck a dirty bomb into NY somewhere! Nah! Were not sure where but we are looking real hard."
Please.
If they had any such weapons in place, I should think they would already have used them, but who knows?
Also, gum bleeding is indeed a recognized symptom of radiation sickness.
Even if you accept what they say, however, I doubt that Debka has any inside information.