Bisphenol A (BPA) was synthesized in 1891 and first recognized as a synthetic estrogen in the 1930s. Chemists later discovered that the individual monomers of BPA could be combined to make two kinds of plastics: polycarbonate and epoxy resins. Commercial production of BPA began in the 1950s when large-scale uses for these products were developed.
BPA-based polycarbonates are used in products such as water bottles, eyeglass lenses, medical equipment, toys, CDs/DVDs, cell phones, consumer electronics, household appliances, sports safety equipment, airplanes, and automobiles. Epoxy resins containing BPA are used as liners for most food and beverage cans, as adhesives, industrial protective coatings, and automotive primers. BPA is also used on thermal receipt paper, to make dental sealants and flame retardants, and is an additive in many other widely used consumer products. It is one of the highest volume chemicals produced worldwide.
‘Leaching’ occurs when the chemical bond linking BPA monomers together to form plastic (i.e., polymerization) breaks. BPA is ingested when it leaches into food and beverages for human consumption. Heating cans to sterilize food, storing acidic or basic food/beverages in cans or polycarbonate plastic, and repeated washing of polycarbonate products all increase the rate at which leaching occurs. People are also exposed to BPA through dermal (skin) exposure.
The human body can metabolize and excrete BPA relatively rapidly. Yet the U.S. Centers for Disease Control and Prevention consistently reports that over 90% of U.S. residents have measurable amounts of BPA in their bodies. This suggests that exposure is continuous and via multiple sources.