Heavy metal and microbial testing limits for dried cannabis

Heavy metal and microbial testing limits for dried cannabis intended for smoking or vaping

Controlled Substances and Cannabis Branch

December 30, 2020

Over the past few weeks, Health Canada has received requests for clarification concerning the selection of appropriate tolerance limits for heavy metal and microbial contaminants in dried cannabis. The information below aims to clarify Health Canada's expectations.

The Cannabis Regulations set out a comprehensive public health approach to regulating the production, packaging and labelling of cannabis. The production of cannabis is subject to strict requirements, including the use of good production practices. The Amended Regulations, which came into force in October 2019, set out rules for new classes of cannabis, for which many routes of exposure for microbial or chemical contaminants are possible (for example, inhaled, oral, dermal).

A change to subsection 93(3) of the Regulations updated the requirements for selecting appropriate tolerance limits for microbial or chemical contaminants for dried cannabis or dried cannabis that is contained in a cannabis accessory that is a cannabis product. The amended regulations require that licence holders use the reference standards which are established in a publication (for example, a pharmacopoeia) referred to in Schedule B to the Food and Drugs Act, and require that the tolerance limits for chemical and microbial contaminants be, "appropriate for the intended use and any reasonably foreseeable use of the cannabis product."

This change to the regulations helps to ensure that licence holders select and use reference standards and tolerance limits for chemical and microbial contaminants that are appropriate for the intended or reasonably foreseeable use of the cannabis product they are producing. For example, in order to reduce risks associated with inhalation, tolerance limits for heavy metals for products intended to be ingested are not appropriate for, and should not be applied to, dried cannabis that is intended to be inhaled (smoked or vaped).

The Amended Regulations included transitional provisions, which provided licence holders until October 17, 2020, to meet the updated requirements. On August 28, 2020, Health Canada communicated it would be temporarily adjusting its approach to its administration and enforcement of the requirements until March 31, 2021, due to the COVID-19 pandemic. The information below aims to assist licence holders as they prepare to meet the requirements by March 31, 2021.

Heavy metals

The toxicity of heavy metals varies greatly depending on the route of exposure (for example, inhalation or ingestion). Generally accepted tolerance limits for heavy metals are different for orally ingested products than for inhaled products. For dried cannabis products that are smoked or vaped, heavy metals could volatilize or adhere to inhaled particulates and become part of the inhaled smoke or vapour stream, and thus the tolerance limits for inhaled heavy metals would be the most appropriate to adhere to in order to reduce health risks to the consumer. For example, the general chapter for elemental impurities in the European Pharmacopoeia (Ph. Eur. 5.20) provides tolerance limits for inhaled heavy metals. Oral limits for heavy metals, such as those found in the Ph. Eur. general chapter 1433 for herbal drugs, would not be considered appropriate for smoked or vaped dried cannabis products.

All licence holders are expected to meet the updated tolerance limits by March 31, 2021, which are not anticipated to be a challenge for licence holders. Consistent with industry best practices, licence holders may choose to undertake certain preventative measures to reduce the risk that heavy metals will contaminate cannabis, such as testing inputs used during cultivation (for example, fertilizers, growing media, soil and water).

Microbial contaminants

Health Canada has received questions on the use of oral microbial limits for herbal medicines for smoked or vaped dried cannabis products and whether limits such as those found in Ph. Eur. 5.1.8 would be considered appropriate. At this time, oral limits for dried cannabis products, such as those found in Ph. Eur. 5.1.8 are deemed acceptable. This requirement remains unchanged since the implementation of the Marihuana for Medical Purposes Regulations in 2014 (now repealed). Should Health Canada become aware of new information that oral limits do not sufficiently mitigate the risk posed by microorganisms found in dried cannabis that is smoked or vaped, Health Canada may review its position in light of the most current evidence.

Additional guidance and information

Health Canada recognizes that the industry is seeking additional guidance on contaminant tolerance limits and testing requirements, and is prepared to develop additional guidance. This guidance would be informed by a wide variety of existing technical documents on product safety and quality control.

For more information on microbial and chemical contaminant tolerance limits, including testing requirements and methods, as well as concepts such as permitted daily exposure, concentration limits and intended and reasonably foreseeable use of the cannabis product, please refer to section 5.3 "Testing requirements" in the Guidance document: Good production practices guide for cannabis.

The information contained in this communication provides an overview of requirements associated with the Cannabis Act and Regulations. It is not intended to provide legal advice regarding the interpretation or application of the Cannabis Act and Regulations or any other relevant legislation. In the event of any discrepancy between the legislation and the content of this communication, the legislation shall prevail.

It remains the responsibility of those engaging in activities related to cannabis, cannabis accessories and services related to cannabis, to understand and comply with the Cannabis Act and its Regulations.

If you have any questions, please contact the Controlled Substances and Cannabis Branch by email at cannabis@hc-sc.gc.ca.