Any plastic that does not fit into the other six well-defined categories of material earns a number 7. Ironically, this category also includes the new bio-based plastics that use corn, potato, or sugar derivatives. However, the most infamous type of number 7 plastic is polycarbonate, a building block in bisphenol-A (BPA), which gained headlines as an endocrine disrupter and raised health concerns. Because this category of plastics is composed of several types of materials, few municipal or commercial programs accept number 7 plastic.