Bisphenol A — 4,4’-isopropylidenediphenol — is an intermediate in producing epoxy, polycarbonate and phenolic resins. Polycarbonates — plastics used in products from microwave cookware to food containers — form by reacting bisphenol A with phosgene; the compound also coats cans. There are concerns that bisphenol A monomers could migrate from cans or containers into foods, with possible endocrine-disrupting effects, prompting regulatory limits, monitoring programmes, and a shift toward BPA-free alternatives in many markets. It remains one of the most studied food-contact substances in regulatory science.