Kurunthachalam Kannan of the Wadsworth Center at the New York state Department of Health and the State University of New York at Albany and colleagues said growing evidence of the potentially toxic effects of BPA -- used in plastics, food packaging and printing -- led some manufacturers to replace it with BPS in thermal paper such as receipts and other products.
BPS is closely related to BPA, with some of the same estrogen-mimicking effects, and there are unanswered questions about whether it is safer, Kannan said.
The researchers analyzed 16 types of paper from the United States, Japan, South Korea and Vietnam.
The study, published in the journal Environmental Science & Technology, detected BPS in all the receipt paper tested -- 87 percent of samples of paper currency and 52 percent of recycled paper.
The researchers estimated 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," the researchers suggested.