was initially used for electrical and electronic applications such as distributor and fuse boxes, displays and plug connections, and for glazing for greenhouses and public buildings. PC's characteristics became popular for many other applications, including plastic bottles and linings for metal-based food and beverage cans.
The use of PC for food packaging received original approval in the 1960s by the FDA under its food additive regulations.
Throughout the decades there were various studies with regards to BPA, but it wasn't until Dr. David Feldman, a medical doctor, and a professor at Stanford University , made a discovery that changed the discussion of PC and BPA forever.
"We weren't looking for this," he said. "It was basically an accident."
During the early 1990s, Dr. Feldman conducted studies on estrogen activity. In 1992, Feldman and his team discovered what looked like an estrogenic molecule when they were growing yeast in plastic flasks. It turned out it was not the yeast synthesizing the estrogen, but rather it was leaching from the plastic. The team then performed an experiment without having the yeast in the flask, and they found there was still this estrogenic molecule in the medium, which they then identified the estrogenic molecule as BPA. They found it was coming from the plastic flask and was not present when they did the experiment in glass flasks.
"We realized that we had identified a molecule that was leaching out of the plastic that, due to its estrogenic hormone-like properties, was potentially dangerous to people eating out of containers made of this type of plastic," he said.
Once they made the connection between polycarbonate, BPA, and estrogenic activity, Feldman and his team contacted a major producer of PC, the former GE Plastics, now Sabic Innovative Plastics , the producer of the Lexan brand PC.
It turns out the company had already looked into the potential leeching issue, but after using their own methods, the company said they couldn't find any estrogenic activity.
While Feldman and his team wrote about their findings, he moved on from conducting research on BPA, but he continued to study findings out of an interest.
"We are still in the same place we were 20 years ago," Feldman said with a sigh. "We are still exposed to this molecule in our food supply, it's in our urine. The question of how bad it is, well, it's still debated."
Bans began with what some called "defending" the most helpless of people—infants.
A 2008 report by the U.S. National Toxicology Program (NTP) found "some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A," with that exposure coming from PC baby bottles and infant cups.
Once baby bottles that were microwaved were found to release BPA into infants' milk, the European Union and Turkey banned the chemical from baby bottles in 2008. Canada also banned BPA in bottles, with Health Canada concluding that chemical was "'toxic to human health and the environment."
Denmark has banned BPA in all