THERE'S COCAINE IN YOUR WALLET, PROBABLY

You've probably got cocaine in your wallet right now.

Toxicology experts say the vast majority of $20 bills in circulation
- -- except for those that are brand new -- have some measurable amount
of cocaine residue on them.

John Hudson, head of the RCMP's toxicology lab in Regina, has written
research papers on drug residue on currency.

Asked what percentage of large-denomination bills in Canada have
cocaine residue on them, he replied: "Virtually everything."

Part of the reason, Hudson said, is that bills are made of a certain
type of fibre that's "very absorbent" of cocaine molecules.

How cocaine gets on bills in the first place is a bit of a
mystery.

"Many years ago it used to be because people who used to inhale
[cocaine] through the nose would roll up a bill, and then the bill
would go into circulation," said Richard Laing, manager of Health
Canada's drug analysis laboratory in Burnaby, which does drug tests
for police.

However, people don't snort cocaine through bills as often as they
used to.

Hudson said the drug may get on bills now through people's fingers --
touching the drug and then touching the bill.

How the drug residue spreads around, however, is less of a
mystery.

Money counters in banks quickly spread the drug residue from one bill
to another, until -- in time -- virtually every bill has some trace of
the drug on it.

Hudson said drug residue has been found on all types of bills, but is
most common on $20 bills -- which stay in circulation longer than tens
and fives.

However, police say there's no reason to be concerned.

Hudson said the average residue of cocaine on a dollar bill is just a
few nanograms -- a nanogram being one billionth of a gram.

In comparison, the smallest thing visible to the human eye, like a
grain of sand, is about one microgram -- one millionth of a gram.

"If you can see it," Hudson said, "it's probably a thousand times more
than what I'm talking about."