Saturday, October 17, 2009

Now there's BPA in cash register receipts?

I haven't posted about bisphenol A (BPA) at all, even though there's been A LOT of coverage on the health concerns of this chemical. First it was in polycarbonate baby bottles, then in the epoxy liners for food cans. Now we find out it's in cash receipts. What's the concern? BPA is an endocrine disruptor (estrogen mimic), and some studies suggest that human exposure to the chemical could lead to negative health effects, such as reproductive problems, obesity, and cancer. Back when I was working in industry, I used BPA quite regularly as a monomer, but of course I was handling it safely, with gloves and in a fume hood.

Apparently, the carbonless copy papers that are used for most credit card receipts and the thermal imaging papers used by most cash registers both rely on BPA chemistry. How does it work? A powdery layer of BPA combined with an invisible ink is coated onto one side of the paper so that when heat or pressure is applied, the BPA and ink molecules react to produce color. Not surprisingly, the quantities of BPA on these receipts are at the milligram level (60-100 mg) -- compare that to the nanogram amounts of BPA that can leach out of polycarbonate baby bottles. Yikes. TIP: Wash your hands well before you lick your fingers...

What's next, BPA in polycarbonate CDs and DVDs? Maybe we're better off going back to vinyl records and VHS tapes.

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