FIPRONILFipronil is a broad-spectrum phenylpyrazole insecticide used to control ants, beetles, cockroaches, fleas, ticks, termites, rootworms, weevils, and other insects. Fipronil is classified as a "possible human carcinogen" by the U.S. EPA. The EU MRL for fipronil is expressed as the sum of fipronil and fipronil sulfone and has been set at 0.005mg/kg (5 ppb). Codex levels typically range from 2 ppb to 20 ppb depending on the food. U.S EPA tolerances for eggs is 30 ppb (40 CFR 180.517). In the summer of 2017, millions of eggs were recalled in Europe, and millions of hens were culled due to suspected fipronil contamination.