… Bt has been used for years as a naturally-derived pesticide; the big difference here is that Monsanto’s gene-splicing wizards made corn and other food-bearing plants grow the Bt internally. When it’s used in organic agriculture you can just wash the Bt off with water; you can’t do that when it’s inside ever cell of the corn you’re eating.
I am well aware of gene injection of Bt into corn. It has been around for a dozen years. I would be willing to bet the residues on garden veggies and what is found in corn grain are quite comparable and well below the no-observable-effect level.