I often wondered as a lot of the explosives used are "cooked" from Fertiliser, why, as they did in Ireland during the troubles, do they simply not make fertilisers with a high nitrate content illegal? there by reducing amount of potential explosive available.
I realise it would be difficult to control, but when stocks of the then illegal fertilisers were discovered they could be destroyed, thus removing a potential bomb making source, Heck you could even supply the safer variant at a cheaper price to the Afghanistanis or replace their discovered stocks with the safer versions........ I would imagine it would be cheaper to give the stuff away than replace some of the vehicles lost, let alone the sad loss of life.
Just a thought.