I can see from the WordPress statistics on this blog that a lot of people are searching for information about bisphenol-A (BPA) in mason jar lids. Apparently word is getting around that Ball and Kerr lids are now BPA-free. The rumor is true: According to Jarden Home Brands, the manufacturer of both Ball and Kerr products, lids produced since last fall have no BPA. Starting this summer, boxes of the lids will be labeled “BPA-free.”
As you might expect, Jarden isn’t saying what chemical or chemicals have taken the place of BPA in the new lids. There are some fifteen other bisphenols, each of them labeled with a different letter or two. At least one, bisphenol-S (BPS), has been thought a safe substitute for BPA. A report published in Environmental Health Perspectives in March of this year found otherwise. BPS, the authors concluded, “disrupts membrane-initiated E2-induced cell signaling, leading to altered cell proliferation, cell death, and PRL release.” E2 is the estrogen estradiol. PRL is prolactin. In other words, BPS messes with your hormones.
Other bisphenols may be at least as dangerous. A report published in the same journal in 2011 concluded, “Almost all commercially available plastic products we sampled—independent of the type of resin, product, or retail source—leached chemicals having reliably detectable EA [estrogenic activity], including those advertised as BPA free. In some cases, BPA-free products released chemicals having more EA than did BPA-containing products.”
Until we have further evidence to the contrary, we can assume that plastic-coated jar lids contain dangerous chemicals, and we should limit contact between the lids and the food we put in jars. Though we can’t keep delivery people from turning packages of gift jars upside down, at home we can take care to keep our jars upright, in the pantry and in the refrigerator.
For more information about BPA and ways to avoid it in home canning, see my article “Home Canning, BPA-Free.”