A potentially harmful compound covers paper money all over the world thanks to paper receipts.

A new study in the journal Environmental Science & Technology found that bisphenol A, commonly called BPA, has contaminated American dollars, euros, Russian rubles and the currencies of 18 other countries.

BPA is a compound commonly used in a range of consumer products, including plastic bottles and thermal paper. According to the news release about the study, BPA also is an endocrine disruptor that mimics the sex hormone estrogen and has a range of potentially harmful side effects.

Thermal paper, commonly used for consumer receipts, is believed to be the primary source of BPA contamination on money. The theory is that when paper money comes in contact with paper receipts — such as when people place receipts in their wallet next to their money — the BPA from the receipt can get onto the paper money.

The researchers gathered 156 pieces of paper money from 21 countries and tested the samples for BPA, with the highest levels of contamination found in money from Brazil, the Czech Republic and Australia.

The Philippines, Thailand and Vietnam had the lowest amount.

BPA traces in American dollars were about average.

While the amount of BPA found on money was higher than in dust in American households, the human intake of BPA through currency was 10 times less than through dust.

This indicates that while BPA contamination of money is widespread, it poses only a “minor” health risk, according to the article.