The world has set off over 1600 nukes since 1945.
How much area is off limits due to those?
The Iranian facilities are underground, calling for an underground detonation. Using a deep penetrator, not much radioactivity should escape.
They may be underground but they had to build airshafts and access tunnels to get topside again. Bombing the sites would surely take out those exposed structures trapping the workers below ground for some time and I doubt they have long term survival supplies and equipment in that event.