There is no easy solution to this problem because for the most part the problem is geographical. Certainly the tanks should be underground and hardened but the ships need to bring the stuff in and if you move the facilities from Haifa you need to take them to another populated region. Ashdod & Eilat are in range of the rockets with longer ranges that Hamas are getting Haifa is in range of rockets from Hezbollah and of course seaborne attacks. You cannot just put the storage facility in the desert because you need port based storage tanks for the ships to store it before it can be transported by road. So what is the solution in a tiny country surrounded by enemies who don't care about civilian deaths?

I suggest to build two or three small continuous production facilities, across the country.

The costs will be MUCH lower than the costs for reparation to the people in Haifa.

Unfortunately, the owners of the ammonia facility in Haifa care more for their own profits and do NOT care about the well being of the people in Haifa.