There shouldn't be a problem. The kill radius of these is measured in hundreds of yards not in miles, and for that reason these press reports about the magnitude of this bomb and the smaller Daisy Cutter are highly overblown.
For comparison purposes, "Little Boy", the bomb that was dropped on Hiroshima, had the explosive equivalent of 20 kilotons - 20,000 tons of TNT. This bomb, massive as it is, comes in at 10 and one half tons. Doing the math, it is .0525 % (five and a quarter ten thousandths) the destructive force of what would now be a minor league nuclear device.
Are MOAB and Daisy Cutter tremendously effective at clearing ground and snuffing cave and bunker dwellers? Absolutely. But I think that has much more to do with what the fuel/air detonation does to the local atmosphere than the sheer power of the bomb.
Now what Iraq has to consider is that a likely response to a WMD attack on us or the Israelis will be something thousands of times bigger. Little Boy caused the deaths of over 100,000 people in a city that amounted to a small suburb of Baghdad. I'm not certain they understand what kind of fire they will play with if they start using biochem.