Cocaine use in Teesside is higher than in most major European cities, according to tests on domestic waste water in the region.
The shocking research was conducted by a group from Teesside University who insist there is no risk to the public from the amounts discovered.
Police in Cleveland said they were “interested” in the study, which showed sustained use of the Class A drug in Middlesbrough and Stockton.
Dr Gillian Taylor, senior lecturer in forensic and analytical science, said the results showed interesting trends across the areas.
“The high levels that we are seeing are comparable with other European cities,” she told the BBC.