We had talked before about how the plastic bisphenol-A (BPA) may cause migraines. Most of our exposure to BPA comes from foods packed in plastic or in cans. However, researchers have now determined that there’s another source of BPA that is especially important for all of us about tax time: register receipts.

Thermal paper contains BPA, HeadachesReceipts Expose You to BPA

Many cash registers use what is known as thermal paper. Register receipts aren’t printed with ink. Instead, they’re coated with a chemical that changes color in response to heat. By heating the paper in specific patterns, the register prints numbers on the paper. In order to function, this thermal paper uses BPA, or sometimes BPS, a variation that seems to have some of the same effects.

It was never known before whether this might constitute any danger, but now a new study suggests that handling register receipts can lead to higher BPA levels. The study recruited 24 volunteers, who provided urine samples at the beginning of the study and after handling receipts for two hours. Researchers found that BPA was found in 83% of urine samples before handling receipts, but in 100% of samples after handling receipts without gloves. BPA levels also increased significantly. However, they found that wearing gloves would prevent rises in BPA levels due to handling receipts, suggesting that skin exposure is what allows BPA to enter the body.

Avoiding BPA-Related Migraines

Since we know that BPA might trigger migraines, it might be a good idea to try to reduce your exposure to BPA via receipts. For anyone who works in retail, gloves begin to seem like a recommended precaution. And any time you’re handling a large number of receipts, such as when you’re doing taxes or expense reports, you should wear gloves to avoid BPA exposure.

This research shows that if you get a headache when doing your taxes, it may not be entirely the IRS’ fault. And it’s worth noting that there’s at least one source of BPA exposure that we’d all be happy to have a little more of. It’s a common ingredient in almost every currency worldwide, including the dollar.