As announced by the Government of Canada, cannabis use has been legal in Canada since October 17, 2018. This legislative change has prompted several economic sectors to consider the impacts of such a change on their practices, and fire safety professionals are no exception. Could the legalization of cannabis lead to an increase in the fire rate in Quebec? Ms. Catherine Dicaire, a chemist at Origin Enquêtes technico-légales Inc. and a former employee of the Quebec Laboratory of Forensic Science and Medicine, shares her insights on the subject.

According to fire safety statistics published by the Ministry of Public Safety, an average of 18,500 fires were reported annually in the province of Quebec between 2010 and 2015. In 2015, in approximately 20% of these cases, the heat source—as recorded by fire prevention officers responsible for investigating the causes and circumstances of fires (RCCI)—was linked to a smoking-related item or an object with an open flame (Ministry of Public Safety, 2018). Could cannabis use contribute to an increase in these statistics?

First, it’s important to know that all cigarettes imported for sale in Canada—or produced here—must be labeled as “reduced fire hazard,” ever since Health Canada enacted legislation in October 2015 aimed at reducing fires caused by smoking products (Health Canada, 2002). In practice, manufacturers can reduce the density of tobacco in cigarettes, decrease the porosity of the paper used, add “flame-retardant” additives, or reduce the circumference of the cigarettes. These measures ensure that cigarettes do not burn completely once lit in more than 75% of cases (according to the ASTM E2187-04 method). U.S. manufacturers, for their part, use a patented process involving the application of concentric paper strips at regular intervals along the length of the cigarette—commonly referred to as “speed bumps”—which slows down and, in some cases, even stops combustion.

Furthermore, few studies have been conducted on the flammability of cannabis cigarettes. The National Association of Fire Investigators (NAFI) published an article on its website in 2016 detailing tests conducted to demonstrate the fire hazard and tendency of tobacco cigarettes to ignite adjacent combustible materials, compared to marijuana cigarettes (Jason J., 2014). The results of this study reveal that the marijuana cigarettes tested—whether hand-rolled or pre-rolled—are less likely to burn completely compared to their tobacco counterparts. Furthermore, it should be noted that this tendency is directly related to the type of cannabis.

Cannabis is an annual plant of the Cannabaceae family native to Asia (Wikipedia, 2018). There are three subspecies or varieties: sativa, indica, and spontanea. These contain several chemicals synthesized by the plant, called cannabinoids, some of which have psychoactive properties (THC), anti-inflammatory effects (CBD), or anti-metastatic properties. The cultivation and hybridization of different cannabis strains make it possible to control the levels of certain cannabinoids in the plant. The part of the plant that is typically consumed is the unpollinated flower of female plants, commonly known as a “bud.” This flower is rich in oil, the concentration of which depends— mong other factors—on the type of cannabis. Some of this oil is retained during processing and ends up in the cigarette. Consequently, when a cannabis cigarette is lit, it tends to go out on its own due to the presence of this oil, which makes combustion more difficult. Furthermore, this oil tends to seep through the paper once it has been pyrolyzed, causing the cigarette to go out naturally.

Although studies show that cannabis cigarettes are more likely to go out on their own and therefore pose a limited danger compared to tobacco cigarettes, the fact remains that smoking materials account for a significant proportion of risk factors for all fires. Consequently, it is certain that cannabis cigarettes will also be implicated. It should not be forgotten that the use of cannabis with a high THC content affects cognitive functions. It will therefore be more difficult to determine with certainty the actions of users prior to a fire if they have consumed cannabis. Furthermore, since reflexes are also affected, cigarette butts are more likely to end up outside of ashtrays—forgotten on a couch or placed in flowerpots.

Furthermore, the artisanal processing of cannabis involves the use of highly volatile and extremely flammable solvents, such as butane or various light petroleum distillates (lighter fluid, camping fuel, naphtha, etc.). Processing involves the evaporation of large quantities of solvent. These vapors then require only a suitable ignition source, such as an open flame (e.g., a lighter, a candle, etc.) or a spark (e.g., a refrigerator starting up, static electricity, etc.) to ignite.

In conclusion, the legalization of cannabis has implications for fire safety and has undoubtedly brought about a change in the field of fire cause and circumstance investigation (FCCI).