Identification of reference values intended to be protective of human health for potential contaminants in hemp plant material and hemp-based products: Part I. Microbial and elemental contaminants

Cannabis use is rising globally in consumer and medicinal products that are ingested, inhaled, or applied topically. Due to cultivation and manufacturing processes, cannabis plant materials and plant-based products may contain detectable levels of microbial and elemental contaminants of human health concern. A review of regulations and identification of toxicological reference values for these compounds in cannabis is necessary to protect public health and guide manufacturers in regions lacking contaminant regulations. This review evaluated international and U.S. state regulations and guidance for impurities in cannabis plant material and final consumer products to identify toxicological reference values for common contaminants. A three-step process was used to identify reference values protective of public health for common microbial and elemental contaminants. An initial literature review of contaminants in cannabis and cannabis-based products was conducted, followed by a focal review of international and U.S. state contaminant regulations. A tiered approach was developed to assess the reliability and relevance of each data source, selecting reference values from Tier 1 and Tier 2 sources. The most conservative values were recommended to best protect human health. While some regions have developed regulations for evaluating contaminants in cannabis products, these vary widely, and significant gaps remain across the industry. In regions without regulations, these discrepancies make it difficult for manufacturers aiming to protect human health to determine which guidance and reference values to follow.