Washington’s Blog 
Sept 24, 2012
Preface: While this post is over-the-top, the serious take-home message is that you should wash your hands after handling paper money and especially paper receipts.
But it may be making you fat.
Specifically, paper money contains bisphenol-A, more commonly known as BPA. The San Francisco Chronicle reported  in 2008:
Twenty-one out of the 22 $1 bills tested in California, 17 other states and Washington, D.C., carried small amounts of the chemical….
The American Chemical Society noted  last year:
The cash register receipts that people place near paper money in billfolds, purses, and pockets has led to a worldwide contamination of paper money with bisphenol A (BPA) ….
Although a recent study found traces of BPA in U.S. currency, nobody knew until now about BPA in paper money worldwide. The scientists’ analysis of 156 pieces of paper money from 21 countries found that all contained traces of BPA.
The highest BPA levels were in paper money from Brazil, the Czech Republic and Australia, while the lowest occurred in paper money from the Philippines, Thailand, and Vietnam. Levels in U.S. notes were about average.
In addition, BPA has linked to diabetes , cancer, metabolic and neurological diseases and reproductive problems .
Many manufacturers have substituted a new chemical – BPS – for BPA. And now BPS is being distributed through paper money.
As Health Day News reported  in July (via Yahoo News):
Many people are absorbing high levels of bisphenol S — a substitute for the chemical compound bisphenol A — when they handle cash register receipts and other types of paper, researchers say.
Concerns about the health effects of BPA have led some manufacturers to replace it with bisphenol S (BPS), which is closely related to BPA and has some of the same estrogen-mimicking effects, the authors explained in the study published in a recent issue of the journal Environmental Science & Technology.
For the study, the investigators analyzed 16 types of thermal cash-register paper, recycled paper and paper currency from the United States, Japan, Korea and Vietnam.They detected BPS on all the receipt paper, 87 percent of the paper currency and 52 percent of the recycled paper.
Science Daily notes :
[A new] report … in ACS’ journal Environmental Science & Technology.
BPS is closely related to BPA, with some of the same estrogen-mimicking effects, and unanswered questions exist about whether it is safer.
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 ….
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.
In fact, many claim that BPS is even more dangerous  than BPA.