Research Brief | Canadian Study Finds Nickel, Chromium, and Lead Particles in Cannabis Vapes, Some Exceed International Limits

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2Firsts, September 2, 2025 — On August 29, 2025, Scientific Reports published a new study entitled “Tracking metal presence in cannabis vaping products from source to inhalation”. The paper was authored by researchers from the National Research Council Canada (NRC), Natural Resources Canada (NRCan), and Health Canada.

This study focused on the potential issue of metal contamination in cannabis vaping products. While vaping is often perceived as a less harmful alternative to smoking, there has been little systematic evidence regarding the presence of metal particles in cannabis vape liquids and whether they are transferred to the aerosol inhaled by users. By combining metal content analysis with aerosol simulation experiments, the research team evaluated the sources, distribution, and potential exposure risks of metal particles in cannabis vapes.

Cannabis vape samples were purchased from the Ontario Cannabis Store (www.ocs.ca). Product details, including THC/CBD concentrations, extraction methods, and additives, were reported in the study.

Key Findings and Conclusions

The research team analyzed six cannabis vape products, each with five cartridges from the same production batch. The study consisted of three main components:

1. Metal Content Analysis of Vape Liquids

All samples contained aluminum (Al), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), tin (Sn), and zinc (Zn).

Certain samples had nickel and chromium concentrations exceeding the United States Pharmacopeia (USP) limits for inhaled products.

Even within the same batch, metal levels varied significantly between cartridges, indicating high randomness and inconsistency of contamination.

2. Aerosol Simulation Experiments

Using a standardized vaping machine, aerosols were collected and analyzed.

All products showed detectable particles of Ni, Zn, Cr, Pb, Co, and Sn in the aerosol, demonstrating that metals can indeed be inhaled.

Although the number of particles was below quantification thresholds, the exposure risk remains a concern.

3. Source of Contamination

Scanning electron microscopy (SEM-EDS) revealed cracks, corrosion, and uneven plating in cartridge components such as connector pins and heating coils. The elemental composition matched particles found in aerosols.

Some unused cartridges already contained metal particles, suggesting that contamination may originate during manufacturing, not only during use.

Conclusions

Both cannabis vape liquids and aerosols were contaminated with metal particles originating from device hardware.

Substantial differences across products and even within batches mean that single-sample compliance testing may underestimate consumer risk.

Potential contamination pathways include material corrosion, mechanical wear, and manufacturing residues.

The critical concern is that these metal particles are carried into aerosols and inhaled, which may pose respiratory and systemic health risks.

Study Limitations (as noted by the authors):

Detection of aerosol particles remains methodologically limited, with some particle counts below quantification thresholds.

ICP-MS cannot simultaneously identify multi-element particles, so particle size estimates may be underestimated.

Device and batch variability reduces generalizability of findings.

Authors’ Recommendations:

Strengthen hardware quality control in vape devices;

Improve regulatory sampling strategies to ensure representativeness;

Increase transparency on device materials, particularly heating coil composition;

Encourage the development of devices that minimize or prevent metal release into aerosols.

Study Information

Title: Tracking metal presence in cannabis vaping products from source to inhalation

Authors: Zuzana Gajdosechova, Joshua Marleau-Gillette, Matthew Polivchuk, Ivana Kosarac, Guru Prasad Katuri, Dharani Das, Ashley Cabecinha, Andrew Waye, Hanan Abramovici

Affiliations:

National Research Council Canada (NRC), Ottawa

Natural Resources Canada (NRCan), Ottawa

Health Canada – Tobacco Control Directorate, Controlled Substances and Cannabis Branch, Ottawa

Health Canada – Office of Cannabis Science and Surveillance, Ottawa

Corresponding Author: Dr. Zuzana Gajdosechova (Zuzana.Gajdosechova@nrc-cnrc.gc.ca)

Publication Date: August 29, 2025 (online)

Journal: Scientific Reports (Springer Nature, Open Access)

DOI: 10.1038/s41598-025-17004-2

Figures in this article are adapted from the original paper. Cover image generated by ChatGPT.

Disclaimer

This article is a summary created by 2Firsts based on a published scientific paper. Its purpose is to make complex research findings more accessible to non-specialist audiences—particularly industry professionals, policymakers, and the media—in order to foster deeper connections between science, regulation, and the NGP industry.

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