Despite many plastics going BPA-free, it's still found in many common items including shopping receipts.

At the end of November, the New York City Council announced that it would be considering four bills that aim to reduce paper waste from store receipts, including the obnoxiously long ones that have become synonymous with shopping at a particular drug store chain. But in addition to reducing the city's collective carbon footprint, the bills also raise the possibility of phasing out the use of receipt paper that is coated with bisphenol A, or BPA.

"Buying a candy bar shouldn’t require a four-foot receipt. Yet many retailers burn through unnecessary amounts of paper while exposing millions of New Yorkers to harmful toxins," Costa Constantinides, the Chair of the Committee on Environmental Protection, said. "I look forward to a day when these receipts are tossed out for good."

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BPA is in a class of chemicals known as endocrine disruptors, because they have the potential to affect normal hormone functions, decrease fertility, and they could be linked to increased cancer risk. Despite manufacturers' attempts to remove BPA from commonly used products like baby bottles, children's toys, water bottles, and canned goods, it is still widely used—and a new study suggests that the U.S. Food and Drug Administration (FDA) has significantly underestimated humans' exposure to the chemical.

In the study, published in The Lancet Diabetes & Endocrinology, the authors explain that the human body quickly breaks BPA down into metabolites. The FDA and other agencies currently measure BPA exposure indirectly, by using an enzyme to convert metabolites in human urine back to BPA, and then measuring the amount of BPA present.

But when these researchers used a direct method of measurement—one that doesn't require the metabolites to be converted back into BPA—they discovered that there was a significant difference between the two numbers. They analyzed urine samples from 29 pregnant women, and used both direct and indirect methods to measure the total BPA level. When using the direct method, the mean BPA level was found to be nearly 19 times higher than the mean BPA level that was detected using the indirect method. ("The same trends were evident" when they used both methods to test urine samples from five men and five non-pregnant women.)

"To our knowledge, our data provide the first evidence that this is a flawed analytical tool for measurement of BPA levels," the authors wrote." Importantly, because estimates of human exposure have been based almost exclusively on data from indirect methods, these findings provide compelling evidence that human exposure to BPA is far higher than has been assumed previously.

"Because negligible exposure levels have been a cornerstone of regulatory decisions, including the FDA conclusion that BPA poses little health risk, the present data raise urgent concerns that risks to human health have also been dramatically underestimated."

According to Consumer Reports, the new study could ultimately change the way that both scientists and regulatory agencies understand past studies that have attempted to measure BPA exposure, and it could also change the way BPA levels are measured, going forward.

Regardless, maybe getting rid of those receipts isn't such a bad idea after all.