[DBrow]

“If you’re making a bomb the urea is all thats necessary (aside from some fuel oil) “

It's more complicated than that. Urea mixed with fuel oil won't explode. You must get almost an equal weight of other chemicals and do a lot of processing first, then use a detonator-booster system.

And even ammonium nitrate-fuel oil takes a considerable amount of booster explosive to go boom. Insensitive explosives are safer and that's why they are used in industry- it's actually very hard to make them “go”.

[HuntsvilleTxVeteran]

True and the speed of the explosion is much slower than
dynamite and it has to be enclosed or dampened much more
than dynamite to get close to fifty percent of the power
of dynamite by weight.