Actually, Anhydrous Ammonia is a low grade refrigerant and is applied in a semi-liquid/gaseous form from a pressure tank, not from bags as a solid. There is a BIG problem with the meth "chemist" trying to collect some by stealing it from the tank wagons. The lucky ones don't get frostbit hands.
Just before Christmas, I worked at a anhydrous ammonia compressing terminus in central Iowa. The maintenance guy related how the product shipped in a pipeline from the Gulf to Iowa and their station was the end of the line. The pressure on the pipeline is about 200 psi. Some meth geniuses decided to put a spigot on the pipeline down the road a ways. He said they found four bodies, a hammer and a punch at the line puncture site when they responded to leak in the morning.
If only the geniuses writing for the New York Times were rewarded so quickly for their mistake of assuming that since it is fertilizer, it must be in a bag.