On May 17th, 2020, twelve firefighters were injured after an explosion occurred at a facility where butane is used for cannabis extraction. It is not yet known if butane was the cause of the explosion but, it was reported that, butane canisters where found in and around the building. The investigation is ongoing.
According to a Politico article, following an uptick in explosions in Colorado, fire officials there persuaded the National Fire Protection Association, which establishes a fire code for the whole country, to amend its rules to address hazards at facilities that grow and extract marijuana. The revised code requires any hazardous extraction process to be performed in a non-combustible room, in a building that contains no child or health care facilities. Staff must be trained on safe operation of the extraction equipment, and the extraction room must be equipped with a gas detection system and multiple fire extinguishing systems.
Extraction
Extraction is a process by which desired chemical compounds are extracted and separated from the cannabis plant. Extraction strips the plant of essential oils, including CBD, THC, and terpenes (aromatic oils that give cannabis plants their distinctive scents). The extracted oils can be utilized in vape pens, edibles, capsules, tinctures, and topical solutions.
Butane is one technique used to separate essential oils from the plant material. The use of butane for extraction is popular owing, in large part, to the relatively low overhead costs, efficiency (including the wide variety of products that can be created from a single extraction, without the need for further refinement), and high product quality associated with this technique. For instance, the low boiling point of butane allow extractors to remove the desired compounds without risking evaporation of, or damage to, the delicate and heat-sensitive cannabinoids and terpenes. Moreover, the low boiling point makes it relatively easy to purge any residual butane at the end of the extraction process, leaving behind only a relatively pure product.
Gas Detection Monitors Can Protect Extractors and Their Employees
While butane is important for extracting essential oils from cannabis plants use of this gas is not without risk, since extraction facility personnel and property are exposed to potential leaks from gas supply lines and storage containers. Butane is highly flammable and explosive gas as well.  Absent appropriate gas monitoring, an explosion can occur if butane vapors are ignited by a spark, heat, or open flame.
Proper gas detection equipment should be placed where the cannabis extraction process takes place, as well as in butane storage rooms, and in any other site where butane may be expected to accumulate. The gas detection equipment should include the capacity to activate visual and audible alarms, stopping the flow of gas and turning on the ventilation system.
PureAire Monitors
PureAire Monitoring Systems has safety monitors to meet the needs of cannabis extractors using butane. Extractors utilizing butane rely on PureAire’s LEL, explosion-proof, combustible gas monitors. The monitor is housed in a NEMA 4 enclosure specifically designed to prevent an explosion. The durable, long-life LEL catalytic sensor will last 5+ years without needing to be replaced.

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PureAire monitors feature an easy to read screen, which displays current levels for at-a-glance observation by employees, who derive peace of mind from the monitor’s presence and reliable performance. In the event of a gas leak, PureAire’s monitors will set off alarms, complete with horns and flashing lights, alerting personnel to evacuate the area. At the same time, the monitors can be programmed to turn off the flow of butane and turn on the ventilation system.
In short, PureAire’s monitors enable cannabis extractors, in a cost-effective manner, to preserve both the quality of their products and the well-being of their employees.

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In 1996, California passed Proposition 215, making it the first of many states to ultimately legalize medical cannabis; as of January 2020, an additional 32 states and the District of Columbia have also made medical cannabis legal. Additionally, recreational use of cannabis is now legal in 11 states and is decriminalized in many others. Cannabis legalization and decriminalization have made cannabidiol (“CBD”, a non-psychoactive compound found in cannabis), and tetrahydrocannabinol(“THC”, the chemical responsible for most of cannabis’ mind-altering effects), available to both recreational users and patients seeking treatment for such health issues as arthritis, anxiety, inflammation, seizure disorders, and nausea.
Since California’s groundbreaking move in 1996, medical and recreational cannabis has become a significant and rapidly growing industry. According to DC-based cannabis researcher, New Frontier Data, legal cannabis sales in the U.S. are expected to reach $30 billion annually by 2025. The industry growth has led to a substantial increase in grow rooms, medical dispensaries and other retail outlets, and extraction facilities.
Extraction
Extraction is a process by which desired chemical compounds are extracted and separated from the cannabis plant. Extraction strips the plant of essential oils, including CBD, THC, and terpenes (aromatic oils that give cannabis plants their distinctive scents). The extracted oils can be utilized in vape pens, edibles, capsules, tinctures, and topical solutions. Based on the end product, various techniques can be used for extracting the oils, including carbon dioxide (CO2) extraction and hydrocarbon solvent extraction (using solvents such as butane or propane).
Carbon Dioxide Extraction
Carbon dioxide, high pressure, and heat can be combined to create a “supercritical fluid” that extracts cannabis components from the plant. The CO2 extraction method generally produces high yields with relatively little waste. Temperatures and pressures can be adjusted to create multiple products including vaporizer oils; dabbing concentrates such as so-called waxes, crumble, shatters, and saps; and distillates (cannabis extracts that have been further purified and processed to separate and isolate the various cannabinoids, which include CBD and THC). Because CO2 evaporates on its own, many in the medical products and food and beverage industries find the CO2 extraction method appealing, since no residual carbon dioxide remains in the final manufactured product.
Hydrocarbon Solvents Extraction
Hydrocarbon extraction typically uses organic solvents such as butane and propane to separate essential oils from the plant material. The use of hydrocarbons for extraction is popular owing, in large part, to the relatively low overhead costs, efficiency (including the wide variety of products that can be created from a single extraction, without the need for further refinement), and high product quality associated with this technique. For instance, the low boiling point of butane, and even lower boiling point of propane, allow extractors to remove the desired compounds without risking evaporation of, or damage to, the delicate and heat-sensitive cannabinoids and terpenes. Moreover, their low boiling points makes it relatively easy to purge any residual butane or propane at the end of the extraction process, leaving behind only a relatively pure product.
Oxygen Monitors Can Protect Extractors and Their Employees
 While CO2 and hydrocarbon solvents are important techniques for extracting essential oils from cannabis plants use of these gases is not without risk, since extraction facility personnel and property are exposed to potential leaks from gas supply lines and storage containers.
Carbon dioxide is an oxygen-depleting gas that is both odorless and colorless. As such, absent appropriate monitoring to detect that a leak has occurred, extraction employees could become dizzy, lose consciousness, and even suffocate from breathing oxygen-deficient air. Hydrocarbons such as butane and propane also deplete oxygen and, they are flammable and explosive as well.
Proper gas detection equipment should be placed where the cannabis extraction process takes place, as well as in CO2 and hydrocarbon storage rooms, and in any other site where CO2, butane, and propane may be expected to accumulate. The gas detection equipment should include the capacity to activate visual and audible alarms, stopping the flow of gas and turning on the ventilation system.
PureAire Monitors
PureAire Monitoring Systems has safety monitors to meet the needs of cannabis extractors, whether they use CO2 or hydrocarbon solvents.
For facilities using carbon dioxide to extract their products, PureAire’s line of dual oxygen/carbon dioxide monitors offer thorough air monitoring, with no time-consuming maintenance or calibration required. The O2/CO2 monitor comes with user-adjustable alarm setpoints for both oxygen and carbon dioxide. The monitor is built with zirconium oxide sensor cells and non-dispersive infrared sensor (NDIR)cells, to ensure longevity.PureAire’s O2/CO2 monitors can last, trouble-free, for over 10 years under normal operating conditions.

Extractors utilizing hydrocarbon solvents, such as butane or propane, rely on PureAire’s LEL, explosion-proof, combustible gas monitors. The monitor is housed in a NEMA 4 enclosure specifically designed to prevent an explosion. The durable, long-life LEL catalytic sensor will last 5+ years without needing to be replaced.
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PureAire monitors feature an easy to read screen, which displays current oxygen levels for at-a-glance observation by employees, who derive peace of mind from the monitor’s presence and reliable performance. In the event of a gas leak, or a drop in oxygen to an unsafe OSHA action level, PureAire’s monitors will set off alarms, complete with horns and flashing lights, alerting personnel to evacuate the area. At the same time, the monitors can be programmed to turn off the flow of gas (CO2, butane, or propane, as appropriate), and turn on the ventilation system.
In short, PureAire’s monitors enable cannabis extractors, in a cost-effective manner, to preserve both the quality of their products and the well-being of their employees.

Criminalization of cannabis cultivation and consumption in the United States began with prohibition by certain states in the early 20th century (between 1911 and 1933, some 29 states banned the cultivation and/or use of cannabis), with the first significant nationwide federal restrictions implemented under the Marihuana Tax Act of 1937.

More recently, just as the states instituted the first cannabis restrictions, so have they taken the lead in relaxing and removing them, first through decriminalization (beginning in the 1970s) and thereafter through legalization of medical cannabis use (beginning in the 1990s) and finally, through legalization of recreational use of cannabis (beginning with Colorado and Washington in 2012).  As of September 2019, medical cannabis was legal in 33 states, while recreational usage was legal in 10 states (with Illinois to follow as of January 1, 2020) and decriminalization in many others. Twenty-six states now permit cannabis cultivation in some form or fashion.

Cannabis legalization has created a significant demand for legally obtainable product, and the cultivation and sale of medical and recreational cannabis has, in a relatively short period of time, become a multi-billion dollar industry in the United States.

Use of Carbon Dioxide to Meet the Growing Cannabis Demand
To help meet the growing demand, cannabis farmers (or “growers”) are raising carbon dioxide (“CO2”) levels to enrich grow rooms, which can shorten the growing season and, therefore, stimulate cannabis production. An increase in carbon dioxide levels stimulates the photosynthesis process, resulting in stronger and faster-growing plants, but the levels must be monitored closely, as too much CO2 can damage plants, as well as present health risks to grow room employees.

Growers typically utilize one of two primary methods to enrich grow rooms with carbon dioxide. The first involves the use of generators to produce CO2 by burning propane or natural gas. This method produces a great deal of heat, which can make if difficult for growers to maintain optimal growing temperatures. Alternatively, compressed carbon dioxide tanks (similar to the ones used in the brewing and carbonated beverage industries) provide the grower with on-demand CO2, and better control over the amount of the gas released, without adding excess heat to the grow room.

Carbon dioxide continues to play an important role in the medical cannabis industry even after the plants have been harvested, because CO2 is an integral part of the process of extracting cannabidiol (or “CBD”, the non-psychoactive chemical compound used to treat conditions such as inflammation, anxiety, epilepsy, and pain, as well as the side effects of certain cancer treatments). Additionally, carbon dioxide is typically used in the packaging process, to help flush oxygen and keep the packaged product fresh.

Carbon Dioxide Monitoring is of Critical Importance in Cannabis Industry
​​To ensure healthy and high yielding cannabis crops, growers must maintain proper CO2 levels, as too much carbon dioxide can lead to lower yields and may even permanently damage the plants. The actual desired CO2 levels may vary depending on the specific cannabis plant varieties being grown, but studies have shown that CO2 levels up to 10,000ppm can significantly increase growth.

However, humans may become disoriented and/or experience respiratory distress when
CO2 levels approach 3,000ppm, and death by asphyxiation is possible at CO2 levels as low as 5,000ppm. Therefore, employee safety concerns demand that cannabis growers and packagers have appropriate monitoring in place.

Proper gas detection equipment should be placed (and secured 12 inches from the floor) in areas, such as grow rooms, where the cannabis growing process takes place, as well as in CO2 storage closets or rooms, and in any other site where CO2 may be expected to accumulate. The gas detection equipment should be capable of activating visual and audible alarms, stopping the flow of carbon dioxide, and turning on the ventilation system.

​PureAire Monitors
PureAire Monitoring Systems’ Dual Oxygen/Carbon Dioxide Monitors offer thorough air monitoring, with no time-consuming maintenance or calibration required. The O2/CO2 Monitor comes with user-adjustable alarm setpoints for each gas. Cannabis growers can set the carbon dioxide alarm to maintain desired CO2 levels inside the grow room, while both the oxygen and carbon dioxide alarms can be programmed to go off when the levels reach an OSHA action level.
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In the event of a leak and carbon dioxide is elevated to levels unsafe for humans, PureAire’s Dual O2/CO2 Monitor will set off an alarm that includes flashing lights and horns, alerting personnel to vacate the affected area. At the same time, the Monitor will turn off the flow of CO2, and turn on the ventilation system.