Most likely, they have something in their process and/or don't want to pay the money to be OMRI certified. I'm sure it is perfectly safe to use, but they have to put the disclaimer in there that it can't be used by people who grow and sell their crops in a 100% organic fashion. If you use their product on your crops and sell them as organically grown, it could come back that you didn't use an OMRI certified product, which could get you into legal trouble. They put that disclaimer on there, so it can't be passed on to them.