CBS Local — A British study has found that many people may be coming into contact with illegal substances like cocaine and heroine during their day, even if they don’t use drugs.

Researchers at the University of Surrey discovered that 13 percent of drug-free individuals had illegal drugs mixed in with their fingerprints. A study of 50 “clean” subjects and 15 people who had reportedly used cocaine or heroin within the last 24 hours revealed that a person’s unwashed hands were being exposed to several chemicals by just shaking hands or touching objects.

“Believe it or not, cocaine is a very common environmental contaminant – it is well known that it is present on many bank notes,” forensic analysis lecturer Dr. Melanie Bailey said in a press release. “Even so, we were surprised that it was detected in so many of our fingerprint samples.”

The scientists added that their tests were able to distinguish between who had been using drugs and who had simply come into contact with a drug-covered item in public. According to the report, the drug traces found on a user were much higher because of the byproducts being released through that person’s pores.

“It’s clear that fingerprint testing is the future of drug-testing,” the study’s lead author Mahado Ismail added. “There are many factors that set fingerprint testing apart – it’s non-invasive, easy to collect and you have the ability to identify the donor by using the sample.”

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