by Rudy Baum
The sad saga of bisphenol A (BPA) and food containers reveals much about what is wrong with some environmentalists today.
C&EN has covered the health concerns associated with BPA extensively for several years. We have covered the reports of the National Toxicology Program on the health effects of BPA and the Food & Drug Administration’s difficult balancing act in regulating human exposure to the chemical.
C&EN has also covered the chemistry that makes it difficult to eliminate all uses of BPA associated with food. Senior Editor Mitch Jacoby, for example, wrote in the Dec. 15, 2008, issue (page 31) that “for many food applications, for example, in the metal-packaging industry, finding a new material with just the right combination of properties remains a major challenge” because “the materials used to coat food cans must adhere strongly, provide corrosion resistance, and withstand the high temperatures required for sterilization and processing. The coating also has to be compatible chemically with the food and cannot impart a flavor or odor.” BPA has all of these characteristics; most potential alternatives do not.
Last year, Senior Editor Melody Voith addressed this issue as well (July 20, 2009, page 28). “Linings made with BPA give a wide range of canned goods their long shelf life and good food safety record,” Voith wrote. “Without any lining, a typical aluminum or steel can creates a strong air and light barrier all by itself. But eventually, contact between the food and the metal will corrode the packaging, leading to spoilage or microbial contamination. Corrosion would rapidly ruin high-acid foods, such as tomatoes. Low-acid foods like peas may last longer but are more likely to harbor toxin-producing bacteria such as Clostridium botulinum.” Alternatives to BPA-based linings do not perform as well and/or are significantly more expensive.
The fact is that the evidence linking BPA with adverse health effects is weak. Many studies have been carried out, and the results have been contradictory. This is why FDA has acted cautiously with regard to BPA and why the chemical and food packaging industries resist stringent regulation of it. FDA announced earlier this year that it has “some concern” about the potential health effects of BPA in infants and children, but also said that more research is needed to fully assess the safety of the chemical (C&EN, Jan. 25, page 8). Market pressure, however, has effectively removed BPA from products such as baby bottles, so that’s no longer an issue.
Nevertheless, the drumbeat against BPA continues. Once suspicion of any kind has been leveled against the safety of a chemical, watch out. No amount of contrary evidence will ever convince some chemophobic environmentalists that use of the chemical should continue. Ban it. Period. It’s no wonder the chemical industry shudders at the mere mention of the precautionary principle.
A front-page story in the Feb. 23 Washington Post, “Replacing BPA in Cans Gives Foodmakers Fits,” carries on in that tradition. Despite the fact that it calls BPA a “synthetic estrogen,” which it isn’t (BPA exhibits weak estrogenic activity, but it is not related to estrogen structurally), the story is, for the most part, factually accurate. Its underlying premise, however, is that exposure to BPA is dangerous. Running throughout the story is the assumption that BPA should be removed from all food containers. A sidebar on the jump page is titled “How to reduce BPA exposure.”
No one has shown that adults exposed to BPA at the levels that leach from food container liners suffer any harm. Potential replacements for BPA don’t work as well and very likely will pose risks of their own. BPA and the polycarbonate plastics and epoxy resins that are made from it are useful chemicals that are getting a bum rap from people who don’t know what they are talking about.
Rudy Baum is Editor-in-Chief of Chemical & Engineering News, a publication of the American Chemical Society