People are being exposed to higher levels of the substitute for BPA in cash register thermal paper receipts and many of the other products that engendered concerns about the health effects of bisphenol A, according to a new study. Believed to be the first analysis of occurrence of bisphenol S (BPS) in thermal and recycled paper and paper currency, the report appears in ACS' journal Environmental Science and Technology.

Kurunthachalam Kannan and colleagues point out that growing evidence of the potentially toxic effects of BPA has led some manufacturers to replace it with BPS in thermal paper and other products. BPS is closely related to BPA, with some of the same estrogen-mimicking effects, and unanswered questions exist about whether it is safer.

Nevertheless, very little is known about BPS occurrence in the environment, the scientists noted. To fill that knowledge gap, they analyzed 16 types of paper from the U.S., Japan, Korea and Vietnam.

The study detected BPS in all the receipt paper they tested, 87 percent of the samples of paper currency and 52 percent of recycled paper.

The researchers estimate that people may be absorbing BPS through their skin in larger doses than they absorbed BPA when it was more widely used - 19 times more BPS than BPA. People who handle thermal paper in their jobs may be absorbing much more BPS.