Pesticides are regulated under a system in which the federal government makes sure pesticides themselves are safe to use, while state governments make sure applicators are trained and actually use the chemicals properly. Pesticides can be registered under Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) for use on a food or feed crop only if a tolerance is first granted. Actually, the federal pesticides law doesn't say a whole lot about how pesticide applicators are regulated. The bulk of the law talks about how pesticides are tested and registered, and only a small section address how to be sure the people who use pesticides are properly trained. The biggest problem was how to interpret FIFRA's requirement that restricted-use pesticides be used only by certified applicators or by someone under the "direct supervision" of a certified applicator.