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Bisphenol A (BPA) was first synthesized in 1891, as a synthetic estrogen by Dianin. Its estrogen properties were not as strong as other estrogens, so it essentially took a backseat. In 1930, the properties of BPA were investigated and it made its return in the 1950s as polycarbonate and epoxy resin; most commonly found in plastic bottles and the inside lining of cans. Due to the increasing popularity surrounding BPA containing products, a carcinogenesis study was done. In the late 1970s, by the National Cancer Institute (NCI) and National Toxicology Program (NTP) tested the safety of BPA. The report stated that the evidence around carcinogenicity effects were not convincing. However, the NTP reported reproductive toxicity.
In 1997 and 1998, Fred vom Saal (right) and his research team published two studies, which investigated the effects of low-dose (below 50 micrograms/kilogram) BPA on mice and found changes in male reproductive organs, as well as, increased prostate weights. A large controversy stirred due to vom Saal's findings; the Society of the Plastics Industry Bisphenol A Task Group and European Chemical Industry Council (CEFIC) responded. Two studies were performed to replicate his findings and neither found negative effects of low-dose BPA use. However, both studies were sponsored by the CEFIC, and BPA producers actually performed one of the studies.
Due to the scrutiny between findings, at the Environmental Protection Agency's (EPA) request, the NTP did a peer review on the BPA issue. The NTP found evidence of negative effects from BPA and thought some testing protocols needed to be revisited. Since there was a consistency of studies that found no negative effects, the EPA did not require screening for low dose response to endocrine disruptors but requested further research.
Organized by the NIEHS, a meeting was held amongst worldwide researchers in Chapel Hill, North Carolina in 2006. Known as the Chapel Hill Consensus Statement, members of the group “reviewed over 700 low dose bisphenol A studies” ( http://www.defendingscience.org/case_studies/Battles-Over-Bisphenol-A.cfm#8 ). It was concluded that there was an increased risk of development disorders (behavioral, metabolic development, reproductive, etc), especially when exposed during the main developmental phase. Contrastingly, the members of the Center for the Evaluation of Risks to Human Reproduction (CERHR) panel, who met in 2007, did not have any experience working with BPA. They concluded negligible and minimal to some concern on issues related to reproductive and birth defects, and behavioral development, respectively.