Fertilizers and a ball mill in a garage is just the classic direct highway route from nothing to pipe bombs, so there are going to be checkpoints along the way.
Fertilizers is what we call "a gateway chemical" first thing you're putting some ammonium nitrate on your crops to make more than break-even this year, next thing you know it's a U-Haul parked up in Oklahoma city. We need to have common sense fertilizer control laws. Mostly it will be police who can use fertilizer, sometimes though we'll let a private detective (ex-police) use fertilizer.