A comprehensive analysis of wastewater samples collected across Australia has uncovered a substantial increase in the use of illicit tobacco products, with consumption rising by approximately 150 per cent over the past seven years.

Researchers from the University of Queensland, drawing on samples from more than fifty wastewater treatment plants that service over half of the nation’s population, found that the proportion of tobacco use attributable to illicit products climbed from roughly nine per cent of total tobacco detected in 2017 to about 33 per cent in recent years.

This trend emerged even as overall measured nicotine levels—reflecting legal cigarette use—declined, underscoring a shifting pattern in how Australians are accessing tobacco.

The study estimated that illicit tobacco consumption increased from around one thousand three hundred and fifty tonnes to approximately three thousand four hundred tonnes nationwide between 2017 and 2023. Researchers used biomarkers specific to tobacco and cross-referenced wastewater findings with national sales and seizure data to strengthen the reliability of their results.

They also noted a marked increase in nicotine from non-tobacco sources such as vaping products, with this category rising from about five point four per cent of total nicotine to more than twenty-six per cent over the same period.

Scientists involved in the research highlighted Australia’s success in reducing smoking prevalence overall through taxation and regulation, but cautioned that the rising illicit market could undermine long-term public health goals.

Although smoking remains a leading risk factor for illness and premature death, the growing scale of unregulated tobacco consumption poses challenges for authorities seeking to reduce tobacco-related harm.

The findings have been referenced in national efforts to monitor and curb illegal tobacco and vaping markets, which also feature in government reporting on illicit substance trends.