HIGH-FLYING executives and working mothers, teenagers and little old ladies:
these days everyone鈥檚 handling cocaine. In most cases, though, they don鈥檛 know
it. They aren鈥檛 smoking it and they鈥檙e not snorting it: they鈥檙e spending it. The
drug is now so widespread that it has contaminated almost every banknote in the
US.
Of course, the amount of cocaine on each note is so small鈥攄own in the
nanograms鈥攖hat you need sophisticated equipment to detect it at all. But
it鈥檚 a gift for lawyers defending dealers and pushers. The smart ones argue that
the discovery of cocaine on their clients鈥� cash proves nothing. And finding
cocaine on their hands is just as meaningless: it could simply have rubbed off
from 鈥渙rdinary鈥� money.
With such widespread contamination, even the skills of sniffer dogs have been
called into question. In 1994, the 9th US Circuit Court of Appeals ruled that
police officers could not seize suspected drugs money or raid premises just
because a sniffer dog had indicated it was contaminated. They would need better
evidence than that.
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Deprived of one of their weapons in the war against drugs, the FBI decided to
track down the source of the problem鈥攁nd find out whether it really did
invalidate the evidence. 鈥淭he extent of the contamination surprised everyone
early on,鈥� says Tom Jourdan, a chemist at the FBI鈥檚 laboratory in Washington DC.
鈥淗ow could the bad guys have touched all that money?鈥�
GAMING TABLES
The answer is that they haven鈥檛. Someone who has handled cocaine, then
touched money will transfer several hundred nanograms to a bill, says Jourdan.
But as the note circulates, the cocaine is spread around onto other notes,
eventually leaving a background level of a few nanograms on each. Snorting a
line of cocaine will leave as much as a milligram on the bill. That could
contaminate half a million bills with an average of 2 nanograms per bill.
Jourdan and his colleague Deborah Wang have been checking banknotes all
around the country, and from every imaginable source鈥攆rom respectable
banks to the gaming tables of Caesar鈥檚 Palace in Las Vegas, from inner-city
streets to the back routes of rural areas. They have detected cocaine on every
batch of bills examined, but nothing to compare with the amounts found on real
drug money.
In their latest study, they sampled bills ten at a time, hoovering the
surface with a specially adapted vacuum cleaner. Then they screened the samples
with a portable ion mobility spectrometer, an instrument that identifies organic
vapours at concentrations of less than a nanogram. If the result is positive,
they take a second sample for more accurate analysis in the lab.
Somewhat surprisingly, banknotes from Miami, the cocaine capital of the US,
gave lower readings than those from Houston. As expected, Manhattan yuppies had
more coke on their money than the people of poor New Hyde Park, but the bills
taken straight off the gaming tables at Caesar鈥檚 Palace had only a fraction of
the cocaine found on notes circulating in Las Vegas suburbs.
The FBI chemists have also examined money from more than fifty real drug
cases. Based on their results, they are confident that finding cocaine on money
can be good evidence in court. The mere presence of the drug proves nothing but
the amount of cocaine can be incriminating. Jourdan puts an upper limit for
background contamination at 30 nanograms per bill. By comparison, the amount of
cocaine detected in criminal cases can be stratospheric. 鈥淲e have found up to
4000 nanograms per bill,鈥� he says.
So, according to Jourdan鈥檚 findings, real drug money is unlikely to be
confused with innocently tainted cash. But could innocent people end up with
drugs on their hands, as some lawyers have claimed? Not even if you handle money
all day, argues Jourdan. Swabs taken from the hands of bank clerks after four
hours of handling money showed no trace of cocaine.
There is a simple explanation for this, says Jack Demirgian of the Argonne
National Laboratory in Illinois, who has scrutinised banknotes with a scanning
electron microscope. This revealed crystals of cocaine trapped in the
criss-crossed fibres of the paper beneath the surface. 鈥淭he cocaine is so stuck
in the fibres that it doesn鈥檛 rub off easily.鈥�
So how does cocaine spread through the money supply so effectively? The
answer, says Jourdan, is that almost every banknote has been in contact with the
automatic money counting machines installed in every bank and post office. 鈥淭he
machines spread the coke around,鈥� he says鈥攁nd he has evidence to support
this idea. The average amount of cocaine on bills is much the same whatever the
denomination. Perhaps even more convincing, the fronts are always more
contaminated than the backs. Because humans are creatures of habit, they
invariably load the counters with all the bills stacked the same way, their
faces in contact with the machine鈥檚 rollers.
The casual contact of fingers may not be enough to loosen the cocaine, says
Demirgian, but the action of the rollers in a currency counter is violent enough
to strip off some of the surface fibres of paper, exposing and picking up the
cocaine below.
And what about those sniffer dogs? Is there really so much cocaine about that
they can no longer make an accurate hit? Not according to Ken Furton at Florida
International University in Miami.
In lab tests with wads of money spiked with varying amounts of cocaine, 15
dogs failed to detect cocaine at the levels found on money in general
circulation. Sniffer dogs do not respond to cocaine itself, explains Furton, but
to a volatile breakdown product, methylbenzoate. This does not form in
pharmaceuticals-grade cocaine, which dogs will ignore even in large quantities.
But street-grade cocaine generally contains about 10 per cent
methylbenzoate.
None of the dogs responded to less than a microgram of
methylbenzoate鈥攕uggesting that it would require far more cocaine than you
would find on 鈥渋nnocent鈥� money to trigger an alert. With money handled in the
normal way鈥攊n small numbers of notes at a time鈥攖he volatile
component of coke quickly disappears. In large wads of notes, the coke is
trapped and methylbenzoate lingers far longer.
鈥淣o one has found methylbenzoate on circulating notes so it鈥檚 unlikely dogs
will react to ordinary money,鈥� says Furton. 鈥淚f a dog responds then there must
be a significant amount of narcotic odour. Dogs are sensitive鈥攂ut only to
a degree鈥攕o you shouldn鈥檛 get false alerts.鈥�