The Food Quality Protection Act (FQPA) of 1996 required the United States EPA to address the issue of endocrine disruption. Since the passage of the FQPA, the US EPA has developed a two-tiered endocrine disruptor screening program (EDSP) designed to examine potential effects of substances on the estrogenic, androgenic, and thyroid (EAT) hormone systems in both humans and wildlife. Tier 1 consists of 11 assays, and is designed to determine whether a substance has the potential to interact with the EAT hormone systems.