In the study, published in Journal of the American Medical Association, researchers measured the amount of BPA in the urine of 24 volunteers before and after they spent two hours handling thermal paper receipts. About a week later, half of the volunteers returned to perform the experiment again, but this time they wore nitrile gloves (the type commonly used in doctor’s offices and hospitals).

In the first group, BPA levels taken four hours after handling receipts were three times higher than they were at baseline; eight hours later, BPA levels were five times higher. But there was no significant increase in the group that wore gloves.

"We now have several hundred studies—including more than 50 in humans—showing health effects from BPA at exposure levels we experience in everyday life, indicating the need for strong safety guidelines to protect public health,” said Laura Vandenberg, Ph.D., assistant professor of environmental science at University of Massachusetts Amherst School of Public Health and Health Sciences, who was the lead author of a recent report analyzing more than 450 studies on the effects of low-level BPA exposure.

“A larger study is needed to confirm our findings, but the results suggest that skin absorption of BPA may be of particular concern to people who handle receipts frequently, such as cashiers,” said the JAMA study’s lead author, Shelley Ehrlich, M.D., of Cincinnati Children’s Hospital Medical Center. Even if you’re not a cashier, you still may be getting more BPA exposure than you realize because thermal paper is also used in airline boarding passes and luggage tags, tickets for trains, movies, sporting events and amusement parks, labels on prescription bottles or packaged supermarket items such as deli meats and cheeses, fax paper, and lottery tickets. A quick test can tell you if the paper you’re handling is of the thermal type. Scratch the printed side of the paper. If you see a dark mark, the paper is thermal.

Some manufacturers make “BPA free” thermal paper, but it’s often coated with a chemical called BPS. According to a 2014 report from the EPA, BPS may pose health hazards similar to BPA because the two chemicals are structurally alike and BPS is also easily transferred to skin.