Aparently, Iran has dug down so deep that nothing we have can touch their nuclear laboratories. Israel, with submarines equiped with nuclear tipped cruise missiles, can strike these sites multiple times. Sure, maybe one won’t knock out a site, but two or three one after another, and finalized with a dirty bomb? Forget about it. They become tombs.
A good bombing would shut down their underground generator exhaust and air supply.
Nothing is completely untouchable no matter how deep they dig their grave.