anecdotal evidence here, but I grew up on a farm. I know exactly what ammonium nitrate is. Here in America the ATF does almost everything it can to keep you from storing or purchasing any more than a sack at a time unless you can prove youve got the soy or corn to feed with it.

a quick Wiki shows Agriculture in Lebanon is the third most productive sector in the country after the tertiary and industrial sectors. It contributes 3.6% to GDP and employs around 4% of the active working population.

Is it feasible for a subset of 216,000 people to steal this chemical rampantly over five years? absolutely. it never goes bad, and you can trade it with neighboring farmers almost like a barter system for things like seed, dung and tractor parts. Should you ever store it? absolutely not, but im willing to venture Lebanese farmers arent millionires and dont really care.

if just 300 people strated looting this chemical theyd only need 20 pounds a piece. theres 3000 tonnes right there.

TL;DR: i do not think this is being used to make explosives.