Cannabis Fire and Explosion Investigations Highlight Industry's Safety Challenges

Andrew Paris

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4 Jan 2024

Legalising cannabis in various regions has guided a new era of economic opportunities and novel challenges. One pressing concern that has emerged prominently is the risk of fires and explosions within the cannabis industry. What exacerbates this issue is the industry's relative youth, which is underscored by the absence of standardised safety protocols and regulations.

In legalised cannabis production facilities, codes and standards cover the construction of buildings and provide the safety of persons and property. Construction and installations must adhere to permitting and contractor licensing regulations. Typically, these installations necessitate inspection and approval from the relevant authority having jurisdiction (AHJ), which could include local building, plumbing, fire or electrical inspectors. Commercial facilities engaging in legal cannabis production and processing are now subject to the standard codes and regulations established by their respective jurisdictions.

Many reasons are behind the increasing number of incidents, such as the production of hash oil (a concentrated cannabis product), electrical problems with overloaded circuits, failures of HID lighting and a lack of industry standards, among many others. Cannabis facilities often deal with volatile materials, such as the gases and liquids used for hash oil extraction. The absence of industry-specific safety guidelines means that many operators may not be fully aware of the risks associated with these processes or how to mitigate them effectively.

At Jensen Hughes, we have investigated dozens of fires and explosions in various legal and illegal cannabis production and processing operations over the years. These include growing operations ranging from one to thousands of plants. Although we have seen an increase in safety now that operations in some areas have been legalised, we still see many of the same issues we find in illegal growing operations.

Unsafe Product Usage, Deficiencies and Operational Practices

It's worth noting that many of the fires and explosions we encountered over time could have been averted if appropriate safety standards had been diligently followed. Nevertheless, it's essential to recognise that strict compliance with safety standards doesn't completely eliminate the risk of fires and explosions. These risks can still arise from unsafe consumer product usage, installation deficiencies, product defects, or inadequate housekeeping and operational practices, such as:

  1. Improper Splicing. Some operators use inadequate methods like twisting and taping splices instead of approved splice connectors, like terminal blocks or wire nuts.
  2. Mixing Dissimilar Metals. Connecting dissimilar metals like aluminum and copper can be problematic. Due to differing coefficients of thermal expansion, these connections may loosen and eventually fail when exposed to heat.
  3. Contamination Risk. Cannabis grow facilities often have humid environments, making them susceptible to contamination by water, liquids, dirt, grease and more.
  4. Poor Plug-In Connections. Loose or poorly connected equipment and extension cord connections can pose a significant hazard. Receptacles may lose their grip force over time, resulting in loose connections.

Improper Electrical Installation

The quality of electrical installations in legal cannabis grow operations has improved, but issues with improper electrical wiring still persist. These problems pose serious hazards, including:

  1. Illegally Bypassing Electric Meters. Some operators splice conductors into the service entrance to bypass electric meters, aiming to avoid high electricity bills from multiple high-output grow lamps. This illegal practice not only poses a risk of lethal shock but also increases the potential for fires due to poor connections.
  2. Directly Connecting Circuits to Main Service Lugs. To save costs, operators sometimes connect feeder and branch circuits directly to the primary service lugs in electrical panels instead of using additional circuit breakers or panels for new equipment. This shortcut poses safety hazards for installers and increases the fire risk due to poor connections.
  3. Improper and Unprotected Splices. Frequently, operators resort to twisting and taping connections instead of using wire nuts, splicing conductors outside of rated junction boxes, or overloading splices with too many conductors. These practices expose operators to shock and fire hazards.
  4. Inappropriately Upgrading Circuit Breakers or Fuses. Some operators replace tripped circuit breakers or fuses with higher-rated ones to prevent tripping rather than address the root cause of overcurrent. This dangerous practice can be mitigated by redistributing loads or upgrading circuits.
  5. Misuse of Electrical Equipment. Using non-UL-listed electrical system equipment or incorrectly using UL-listed equipment is a common mistake. Local and state electrical codes often require UL-listed or similarly rated equipment to ensure safety.

Addressing these electrical wiring issues is crucial to enhance safety and reduce the risk of electrical fires and accidents in legal cannabis cultivation facilities.

Exposure to Multiple Ignition Sources

Traditionally, cannabis grow operations have utilised high-power, high-intensity discharge (HID) lighting. This presents several hazards, including combustibles touching the extremely hot lamp glass, mechanical damage causing glass breakage and potential plant or material ignition, and lamp failure due to oil or grease contamination.

Other lighting options like full-spectrum fluorescent and LED fixtures also carry their own dangers, such as installation defects, incorrect electrical connections, voltage supply issues, and substandard ballasts or power supplies. Fluorescent lights, in particular, can pose a fire risk when the lamps are misaligned during installation.

THC-containing hash oil can be extracted from cannabis using butane as a solvent, often on a small scale. Butane evaporation is the most hazardous phase of this process, as butane fumes are highly flammable and explosive. Butane, being heavier than air, can accumulate at floor level and pose a severe risk. Improper extraction methods or unsuitable environments can lead to fires or explosions, with common household appliances inadvertently acting as ignition sources.

Be Aware of Potential Hazards

Many issues and fire causes have been faced in different cannabis production and processing facilities where our team of experts have investigated the origin and cause of a fire. It's essential to be aware of these potential hazards to ensure the safety of individuals and property in the cannabis industry. Safety can be maintained through careful designs, proper installations and adherence to manufacturer instructions, local electrical codes, and building regulations. Such measures are crucial for safeguarding employees, property and overall operations.

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About the author

Andrew J. Paris
Drew Paris, PE, CFEI, CVFI, Director, Forensic Electrical Engineering, specializes in investigating and consulting on electrical fires and failures, electrical design and electrical safety.