Testing used cars for drug traces

Environmental health experts at Flinders University have found most surfaces in a car retain traces of methamphetamine after it’s been smoked in the vehicle, putting subsequent users of the car at risk of third-hand exposure to the drug.

First author Gemma Kerry, left, with coauthors on the study Professor Kirstin Ross, Associate Professor Stewart Walker and environmental scientist Dr Jackie Wright in the lab.

Small-scale testing of two used vehicles, under special licence and controlled conditions, found meth in 85% of surface wipe samples and 93% of bulk material samples after simulated smoking events. All six air samples detected methamphetamine.

“Testing and remediation for methamphetamine in contaminated vehicles is necessary to protect public health,” says Professor Kirstin Ross, from the College of Science and Engineering.

“Cars can be used to smoke, manufacture and transport methamphetamine and subsequent passengers or drivers of contaminated vehicles could be exposed to the drug, third-hand.”

Individuals exposed to indirect contamination may have adverse health symptoms including respiratory problems, headaches and behavioural and cognitive issues. This makes it important to determine the overall methamphetamine contamination extent of cars to provide the public with safeguards when buying or using vehicles, the Flinders University experts say.

Flinders experts including PhD in Forensic Chemistry and Environmental Health, Gemma Kerry, whose research is investigating the risks of third-hand contamination from meth, have published the latest results in a new article in Forensic Chemistry.

Testing for signs of the drug being transported in a car boot.

The study was undertaken to determine the extent and distribution of contamination on surfaces, in air and from porous materials in two cars that tested positive for methamphetamine. One of the two vehicles was earmarked to be destroyed.

“These results demonstrated that methamphetamine can be detected in air, on the surfaces of non-porous and porous materials, as well as from within porous materials,” says Ms Kerry.

“The results also demonstrated that methamphetamine was still able to be detected from a second, third and fourth wipe sampling event of a plastic surface, indicating that there is a necessity for further research on testing and remediation in cars.”

Law enforcement agencies, vehicle dealerships, vehicle lenders and owners are challenged with testing and cleaning contaminated vehicles, in particular stolen or second-hand cars.

Another author, Associate Professor Stewart Walker, says: “Detecting the presence and concentration of methamphetamine in different areas of the car can give us clues as to what led to this contamination. For example, high concentrations in the roof lining above the driver or each of the passengers indicate who was smoking, whereas higher levels in the boot indicate transport of the drug there.”

An article ‘Determining extent and distribution of methamphetamine in cars: Air vs. surface vs. fabrics’ (2025) by Gemma L Kerry, Kirstin E. Ross, G Stewart Walker and Jackie Wright will be published in the March edition of  Forensic Chemistry and is now available online ahead of print. DOI: 10.1016/j.forc.2024.100628.

All testing activities were done with Flinders University Risk Assessments and under Government of South Australia, SA Health, Research, Instruction, Training or Analysis Permit (Controlled Substances Act, 1984 Permit Number: 2024-83442).

Background:

Methamphetamine can be manufactured in vehicles in transportable and generally small-scale clandestine laboratories. Additionally, private and commercial vehicles can be used for transportation or smoking of the drug.

Gemma Kerry, PhD in chemical forensics and environmental health, at Flinders University’s College of Science and Engineering.

Both manufacture and smoking releases drug residues emitted as particulate matter or as the free base in the vapour phase resulting in contamination of the surrounding environment. These residues can deposit onto surfaces, become embedded in porous materials, and can further transfer.

Little is known about the extent and distribution of methamphetamine in vehicles such as cars, though contamination would be expected to occur throughout the heating, ventilation, and air-conditioning system, upholstery, interior roof lining and carpets. The distribution and relative concentration of contamination may indicate different activities.

Individuals occupying the car post cooking or smoking could then be exposed to meth through dermal adsorption, ingestion from hand-to-mouth behaviour, and inhalation routes, resulting in third-hand exposure. Third-hand exposure to methamphetamine (or ‘THEM’) symptoms include headaches, respiratory problems, behavioural and cognitive issues, skin rashes and eye irritation.

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