Aspergillus in the Cannabis Industry: Understanding Potential Health Issues and Pain Points

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Aspergillus is a genus of mold that is commonly found in the environment, including soil, plants, and decaying organic debris. In fact, there are several hundred species of Aspergillus! Aspergillus species produce aflatoxins, which are a family of mycotoxins produced by certain fungi. These aflatoxins are known as cancer-causing substances and pose a dangerous threat to humans and livestock. Although this type of mold is commonly grown underground, the release of its spores into the air is the route of the problem in terms of contaminated product. Given there are many species of Aspergillus that are not harmful, a select few can cause life threatening issues. We aim to cover short Aspergillus topics in hopes to educate and clarify conversations surrounding this fascinating fungus. As cannabis products become increasingly popular for both medical and recreational purposes, understanding the potential health issues associated with Aspergillus contamination is crucial.

Aspergillus Exposure

While many species of Aspergillus are harmless, some species can be potentially dangerous to humans. And though most people are exposed to Aspergillus in spore form on a regular basis without any adverse effects, certain species within this genus can produce mycotoxins, which are harmful compounds that can lead to major health issues in humans.Aspergillus can release incredibly small spores into the air. If these spores reach our sensitive respiratory system, they can cause various health issues. The lungs are a perfect breeding ground for the fungus and can quickly lead to infection. The infection can take a gnarly turn for individuals who have weakened immune systems or underlying respiratory conditions. If the infection is not treated early, it can cause serious and sometimes fatal bleeding in the lungs.

Health Impacts

Breathing in these contaminated spores causes a slew of known health issues. Fumigatus is the most prevalent Aspergillus species of fungus causing disease and is the leading cause of aspergillosis causing chronic pulmonary infections. Aspergillosis is a condition in which fungi infect the tissues. The most common manifestation of Aspergillus infection is allergic bronchopulmonary aspergillosis (ABPA), which is an allergic reaction in the lungs.

Here are some potential health issues related to Aspergillus exposure:

  1. Respiratory Problems: Inhalation of Aspergillus spores can lead to respiratory problems, particularly in individuals with respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD). Exposure to high levels of Aspergillus spores can trigger allergies, asthma attacks, and other respiratory symptoms.
  2. Allergic Reactions: Aspergillus exposure can lead to allergic reactions in some individuals. This can manifest as symptoms like sneezing, coughing, runny or stuffy nose, itchy or watery eyes, and skin rashes.
  3. Invasive Aspergillosis: The most serious health concern associated with Aspergillus is invasive aspergillosis, a severe fungal infection that primarily affects individuals with weakened immune systems. This includes patients undergoing organ transplants, individuals undergoing chemotherapy, and those with advanced HIV/AIDS. Invasive aspergillosis can lead to pneumonia, fever, chest pain, and even death if not promptly treated.

Individuals can also contract aspergillosis in a surprising way…via organ transplants and stem cell transplants. Aspergillus is the most common invasive mold infection in solid-organ transplant (SOT) recipients, and it is the most common invasive fungal infection among lung transplant recipients. Because of the increased risks of contracting aspergillosis via organ transplants, there are many transplant programs who will remove patients who use cannabis from their donor recipient list.


Known Aspergillus Cannabis Cases

Sadly, there are several studies linking cannabis inhalation use and invasive aspergillosis. Invasive Aspergillosis has been described in association with cannabis smoking in two cancer patients on chemotherapy, two leukemia patients, a renal transplant recipient, and a few patients with AIDS. In a 2011 study, chronic pulmonary aspergillosis (CPA) was associated with cannabis smoking. This study detailed the unfortunate case of a patient passing away at just 34 years of age and another patient at 46 years of age.

Concerns for Cannabis Users and Manufacturers

Like many other crops, cannabis plants can be susceptible to fungal infections, including Aspergillus. If cannabis is grown or stored in conditions that are conducive to mold growth, such as high humidity or improper drying and curing processes, it can provide an environment for Aspergillus to thrive.

When contaminated cannabis is consumed via the respiratory tract, it can potentially pose health risks, particularly for individuals with weakened immune systems or respiratory conditions. The issue with fungus spores and cannabis is when its spores are introduced into the lungs, for example, by smoking and inhaling contaminated product. This is especially concerning if the plant material is tainted with fumigatus spores and is introduced into the lungs, which could create a perfect environment for infection. Infused edible products are typically not a concern when it comes to Aspergillus because the stomach is not conducive for the spores to survive.

Here are a few examples of pain points in the cannabis industry:

  1. Lack of Regulations: One of the primary challenges in the cannabis industry is the lack of standardized regulations for mold and mycotoxin levels in cannabis products. Unlike food and pharmaceutical industries, there are no universally accepted limits for mold contamination in cannabis unless established in specific states by state regulators. Many have no regulations at all when it comes to Aspergillus.
  2. Quality Control and Testing: Ensuring the safety of cannabis products requires robust quality control and testing procedures. However, not all cannabis producers adhere to strict testing protocols, and some products may reach consumers without thorough screening for mold contamination. This is why so many companies are wanting certifications such as good agricultural and collection practices (GACP) and current good manufacturing practices (cGMP) to reduce the risk of cross contamination and selling products that could be contaminated.
  3. Indoor Cultivation Environments: Cannabis is often cultivated indoors, creating an environment conducive to mold growth if not properly managed. Factors such as humidity, temperature fluctuations, and inadequate ventilation can contribute to the proliferation of molds like Aspergillus.
  4. Product Diversity: The cannabis industry offers a wide range of products, from flower to edibles and concentrates. Each product type poses different challenges in terms of mold prevention and detection. For instance, mold contamination in edibles and concentrates is not as common as it is in dried flower.

Mitigation and Prevention

To address the potential health risks associated with Aspergillus contamination in the cannabis industry, several measures can be taken:

  1. Regulations and Guidelines: Governments and regulatory bodies should establish clear guidelines and limits for mold and mycotoxin contamination in cannabis products. Because of issues with testing laboratory consistency this can be challenging. May times having a limit rather than requiring a “non-detect” test result can make it easier for different laboratories to become more consistent. This is an ongoing issue with many contaminates, not just Aspergillus.
  2. Quality Assurance: Cannabis producers should implement rigorous testing and quality assurance processes to detect and prevent mold contamination. This includes regular sampling and testing of raw materials and finished products. Many companies are getting certifications such as GACP and cGMP to help with quality assurance and reduce the risk of all issues when it comes to contamination.
  3. Cultivation Practices: Proper cultivation practices, including maintaining optimal humidity levels, ensuring proper ventilation, and implementing mold prevention strategies, are crucial to minimizing the risk of Aspergillus contamination. Getting GACP certification is a cultivation is a great way to keep your cultivation practices above board and consistent.
  4. Education and Awareness: Educating both producers and consumers about the risks of mold contamination and the importance of safe handling and consumption practices can play a significant role in minimizing health risks. All certifications require in-house training that is very beneficial to all employees and the facility as a whole.


Given that there are many types of illness causing microbiological contaminants, some states have only just required testing for Aspergillus. In 2023, new rules were established by the Oregon Health Authority (OHA) that finally involve required microbiological contaminants (including Aspergillus) testing for cannabis and hemp products. Specifically, OHA requires testing for these types of Aspergillus molds: pathogenic aspergillus flavus, fumigatus, niger, and terreus.

Other states requiring Aspergillus testing include Alabama, Alaska, Arizona, California, Colorado, Connecticut, Delaware, Florida, Hawaii, Iowa, Michigan, Mississippi, Missouri, Montana, Nevada, New Mexico, New York, South Dakota, Utah, Vermont, and West Virginia.


Inhaling Aspergillus spores can lead to respiratory problems, allergic reactions, or even invasive aspergillosis. This is why it is important to ensure that cannabis is grown, processed, and stored under appropriate conditions to minimize the risk of Aspergillus contamination. Quality control measures, focus on preventive rather than reactionary, and regular testing for molds and other contaminants, can be implemented in the cannabis industry to ensure consumer safety. It's important to obtain cannabis products from reputable sources that adhere to strict quality standards to minimize the potential risks associated with Aspergillus or other contaminants.

About the Author

Kim Stuck is the CEO and founder of Allay Consulting. Direct correspondence to: