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The risky business of marijuana butane honey oil operations

Fires and explosions occurring at marijuana butane honey oil extraction (BHO) operations have increased significantly over the past several years, according to the Office of the Fire Marshal and Emergency Management (OFMEM) in Ontario.

June 13, 2018  By Jason M. Williams

There are inherent hazards and dangers associated with the extraction process due to the volatile fuels utilized by the manufactures of the illicit marijuana concentrate product. The incidents, which are occurring at illegal drug producing facilities, have caused serious injuries, property damage and even death to those involved in the manufacturing process as well as members of the public. It is an issue all first responders must be prepared to handle, especially as the legislation governing marijuana is set to change in Canada.

Between 2012 and April 2018, the OFMEM investigated 39 fire/explosion incidents involving BHO extraction processes in the province.

The BHO method of producing marijuana concentrate allegedly provides a greater yield than other methods and has become very popular. Information on how to carry out a BHO extraction can be found readily online and does not require any specialized equipment — it can all be purchased at a local hardware store.

A background on marijuana concentrate production
Hash oil is manufactured by solvent extraction of marijuana and/or hashish. After filtering and evaporating the solvent, a sticky resinous liquid remains. One pound of marijuana will produce between 1/5 and 1/10 of a pound of hash oil.


(As a side note, hash oils seized in the 1970s had THC contents ranging from approximately 10-30 per cent. Hash oils seized in the past five years have had THC concentrations as high as 90 per cent.)

A wide variety of solvents can and have been utilized for the extraction process including chloroform, petroleum ether, naphtha, benzene, ethanol and butane.1 Here we will focus on the utilization of butane as the solvent.

The preferred method to produce marijuana concentrate is to manufacture BHO, which regularly utilizes a four-step process. The manufacturers of the BHO will moderate the amount of marijuana plant material (which includes buds, stems and leaves) by grinding the material into smaller particulate with a grinder or blender; the smaller particulate is commonly known as “shake.”

This material is then placed into an extractor tube, which can be made from PVC piping, glass mason jars, glass piping materials and stainless steel piping along with extractors. One end of the extractor is equipped with a receiver that will accommodate a butane canister dispensary nipple and the other end will be covered with a filter (coffee filter, cheese cloth). A collection device (bowl or dish) is placed under the filtering device to collect the product at this stage.

The extractors can vary in size, shape and can be made out of an array of materials. Commercially available extractors are also available, such as Close Looped Extraction systems, which often utilize refrigerant cylinders to store the butane.

The butane is stored in liquid form in the commercially available cylinders, which are sold predominantly for the purpose of refilling cigarette lighters.

The process strips the cannabis marijuana of its cannabinoid rich oils and THC-containing materials by using the butane to break off and dissolve the trichomes into the solvent, carrying it away from the plant material where it is further refined by the manufacture of the BHO.

The manufacturers of the BHO then attempt to refine or purge the product of any impurities or butane fuel by soaking the collection dish/bowl with a solution of warm water in a double boiler system or crock pot(s). Another common method is the use of a vacuum pump attached to a vacuum chamber and/or oven.

Some of the manufacturers of the marijuana concentrate will attempt to further refine the BHO product into “shatter,” which continues with the attempts to purge the product of any impurities and is known as “winterizing” or “de-waxing.” These steps of the process remove the marijuana plant wax from the hash oil.

The manufacturer places the BHO product into a container (such as a mason jar) and pours acetone, toluene, grain alcohol or 99 per cent-pure isopropyl alcohol into the container with the product, which is then often placed into a freezer.

The fuels utilized in the BHO operation (butane, isopropyl alcohol, etc.) have explosive properties. The intentional introduction of the fuels into a compartment only requires the diffused fuel/air mixture within the explosive range and a competent ignition source to potentially cause an explosion.

The factors affecting the dynamics of the explosion incident and pressures created by the diffused fuel vapour explosion are the fuel-air ratio, turbulence effect, volume of the confining space, location and magnitude of the ignition source, venting and strength of the structure.

Explosions occurring at BHO manufacturing facilities have completely destroyed single-family dwellings, business and industrial facilities, along with causing serious life-threatening injuries and death to individuals in or near the site.

BHO fire and explosion incidents are becoming a more regular occurrence in Ontario. These explosion investigations are being under taken by the OFMEM along with local fire and police services.

Insuring the proper legal authority to conduct such an investigation is required by all of the agencies involved. Often the scene results in parallel investigations; a narcotics investigation and a fire/explosion investigation. Under these circumstances both a Control Drug and Substances Act search warrant and an s. 487 Criminal Code search warrant should be sought, as any authority under the Fire Protection and Prevention Act would not be applicable in this instance.

Law enforcement response
In February of 2013 the Federal Emergency Management Agency (FEMA) posted an alert in its emergency services bulletin titled “Hash Oil Explosions Increasing across U.S.”

The alert was in relation to an increasing number of explosion incidents occurring where “a process using butane to extract and concentrate compounds from marijuana,” was being utilized. These destructive incidents that FEMA identified could even be mistaken for pipe bomb or meth lab explosions.2

In 2012, the state of Colorado de-criminalized possession of marijuana for medical purposes, regulating it like alcohol. Since the de-criminalization of marijuana there have been a reported 55 explosions in the state, all associated with the illegal production of marijuana concentrates.3

United States law enforcement agencies have identified a rise in the number of BHO explosion incidents in states that have de-criminalized possession of marijuana for medical purposes, especially on the west coast of the country.4 The Drug Enforcement Administration (DEA) and local law enforcement agencies throughout the United States have implemented task forces to deal with the rising concern in relation to the illegal operation of marijuana concentrate extraction laboratories.

The Royal Canadian Mounted Police, municipal and provincial police agencies in Ontario have all indicated that BHO operations have been identified in numerous areas.5 In other words, these types of explosions won’t be going away any time soon.

In Ontario, individuals who are prosecuted in relation to an explosion at a BHO manufacturing laboratory are regularly charged under Section 433 of the Criminal Code of Canada which states, “Every person who intentionally or recklessly causes damage by fire or explosion to property that is not wholly owned by that person is guilty of an indictable offences.”

Sections 434.1 and 436.(1) also apply and may be laid in relation to a fire/explosion related to a BHO operation.

It is clear that the intentional introduction of butane into a confining vessel or compartment for the purposes of the illicit manufacturing of BHO is an extremely hazardous and dangerous process.

With the upcoming legalization of marijuana in Canada, the likelihood of an increase in BHO laboratories and subsequent explosion incidents in Ontario can be expected, as has occurred in many areas of the United States. This put the manufacturers, members of the public and first responders all at an inherent risk of an explosion and/or fire incident.  

1. Klein, S. (2016). Butane Hash Oil Manufacturing: It’s a Fire Service Problem Too. Fire Engineering, 13.
2. Hallet, A. (2013). Hash Oil is Blowing Up Across the U.S.-Litterally. Wired, 2.
3. Klein, S. (2016). Butane Hash Oil Manufacturing: It’s a Fire Service Problem Too. Fire Engineering, 13.
4. DEA, U. S. (2014). What you should know about Marijuna Concentrates. Washington, D.C.: US Department of Justice.
5.  News, C. (2015, March 19). “Shatter” drug now on police radar in Ontairo. Retrieved January 10, 2017, from CBC News.

Jason M. Williams is a fire and explosion investigator with the Office of the Fire Marshal and Emergency Management. You can reach him at

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