Manufacturing cannabis products starts with the plant. The plant is the alpha and omega of cannabis oil extraction and production. There are several ways to extract oil from cannabis (utilizing solvents such as super-critical CO2, ethanol, or hydrocarbons) (See Appendix G). Each method has its pros and cons. Some are safer and more effective than others. It’s not rocket science. Other industries successfully employ the same extraction technologies in accordance with already established safe manufacturing standards.
The purpose of extracting oil from cannabis is to make CBD, THC, and other components of the plant available in a highly concentrated form. After it is extracted from the plant matter and the solvent is removed, the CBD-rich (or THC-rich) oil may be refined and formulated into a variety of consumable products – edibles, tinctures, soft gels, vape oil cartridges, beverages, topicals, and more.
But many CBD products are manufactured without regulatory oversight and the quality of these products can vary greatly, depending on several factors, most notably: the health of the soil in which cannabis is grown; the presence of pesticide and solvent residues in the oil extract; and the problematic use of toxic thinning agents and flavor additives that may have adverse health effects.
Question 2: Bioaccumulation & Heavy Metal Contamination
Cannabis is a remarkably proficient “bio-accumulator”— meaning the plant naturally sucks up toxins from the soil. 35 That’s wonderful for restoring a poisoned landscape, but it’s not so great for making ingestible and inhalable medicinal oil products. Oil extracted from cannabis will concentrate heavy metals and other toxins drawn from the soil in which it’s grown, along with the CBD and other desirable plant components. 36 The phyto-remedial properties of cannabis underscore the importance of cultivating resin-rich plants in a clean environment.
CBD oil is extracted from the resinous trichomes of cannabis plants. The amount of CBD and THC present in the trichomes will depend on the particular variety of cannabis or hemp. Low-resin industrial hemp (legally defined as cannabis with less than 0.3 percent THC by dry weight) has fewer trichomes – and therefore less oil – than high-resin cannabis varietals (marijuana). Therefore, a large amount of hemp biomass is required to extract a relatively small amount of CBD oil – which increases the risk of contaminants.
Compared to high-resin cannabis, low-resin industrial hemp is more vulnerable to pest and mold infestation because the resin contains terpenes as well as cannabinoids that repel predators, attract beneficial insects, and protect plants from blight. With increased risk of pests comes an increased risk of pesticide and fungicide applications, which can be concentrated into toxic levels when cannabis oil is extracted from the flower.
Question 2: Pesticides, Fungicides & Solvent Residues
There are many ways to administer cannabis products, and this poses unique challenges to regulators who are tasked with setting allowable limits for heavy metals, pesticides, and solvent residues. Problems have arisen in part because regulators don’t always take into account how CBD and various cannabis products are actually consumed. Different modes of administration (ingesting, smoking and vaping) may warrant different allowable action limits to protect cannabis and CBD consumers from toxic exposure, as Project CBD indicated in a report to California’s Bureau of Cannabis Control (See Appendix H). This report presented a detailed critique of California’s testing requirements for cannabis products and emphasized the following:
- Federal and state agencies have compiled safety data pertaining to the oral ingestion of pesticides and solvent residues, but there is little safety data regarding smoked or vaporized pesticides and solvents. That’s because the tobacco industry lobbied to ensure that scientific data on health and safety was not used to inform laws or regulations. Tobacco’s poor regulatory standards with respect to pesticides should not serve as a model for the emerging cannabis industry.
- Relatively little is known about the health effects of heating or burning pesticides. Some pesticides will become safer when burned, while many others will break down into much more toxic compounds. Pesticides degrade into stronger toxins at temperatures that cause cannabinoids to vaporize. The widely used pesticide myclobutanil, sold as Eagle-20, decomposes into hydrogen cyanide when heated.
- Regulations need to be based on sound scientific data. If safety data on burning and inhaling pesticides is not yet available, then there should be provisions for updating and adjusting allowable limits as more toxicological data becomes available.
- Solvents are classified into one of three groups by the FDA. Given that cannabis oil can be safely extracted with Class 3 solvents like ethanol and butane, we recommend banning the use of all highly toxic Class 1 solvents, including benzene, as unsafe and unnecessary. Project CBD further recommends that regulators work with cannabis product-makers to determine if Class 2 solvents, such as chloroform and dichloromethane, are necessary for extracting CBD and other cannabinoids. If safer options are viable, Class 2 solvents should also be banned for use in manufacturing cannabis extracts.
- There should be a zero-tolerance policy for spraying cannabis with neonicotinoids (e.g., acetamiprid, imidacloprid), pesticides which are a factor in the worldwide decline of bee populations.
- Mold is one of the most common contaminants found on cannabis. It is essential that products made from low-resin hemp or high-resin cannabis be tested for mold. California’s regulations for mold on cannabis products are far too lax, as Project CBD noted in its critique of California’s revised regulatory requirements (See Appendix I).
Well-regulated testing requirements are essential for the legal cannabis industry and the consumers that it serves. Labs should be certified by groups such as the International Organization for Standardization or the International Electrotechnical Commission to ensure the accuracy and consistency of analytical data, which has been problematic in the past.
Question 2: Toxic Thinning Agents & Flavor Additives in Oil Cartridges
Many CBD consumers assume that vaping cannabis or hemp oil is a healthier method of administration than inhaling smoke, which contains noxious substances that can irritate the lungs. Theoretically a vaporizer heats the cannabis oil concentrate without burning it so the active ingredients are inhaled but no smoke is involved. 37 But there may be a serious downside to vaping CBD oil and other cannabis oil extracts. Vape pens contain a battery-operated heating mechanism, which at high temperatures can transform solvents, thinning agents and flavor additives into carcinogens and other dangerous toxins. Project CBD has been sounding the alarm about potential harms from vaping poor quality, hemp-derived CBD oil since 2015, a year before e-cigarettes came under the FDA’s regulatory control (See Appendix J). Here are some of our concerns:
- Many vape oil cartridges include propylene glycol (PG) or polyethylene glycol (PEG) as a thinning agent, but neither has been safety tested by the FDA for inhalation when heated. Because of low oral toxicity, PG is classified by the FDA as “generally recognized as safe” for ingestion as a food additive. PG is also the primary ingredient in a majority of nicotine-infused e-cigarette solutions. At high temperatures, PG and other vaping additives convert into carbonyls, a group of cancer- causing chemicals that includes formaldehyde, a toxin linked to spontaneous abortions and low birth weight.
- To date there is no conclusive evidence that frequent users will develop cancer or other illnesses if they inhale the contents of vape oil cartridges. That’s because little is actually known about the short-term or long-term health effects of inhaling PG and other ingredients that are present in flavored vape pen cartridges. Many of these prefilled cartridges are poorly labeled with little or no meaningful information on their contents. The possibility that vape pens might expose people to unknown health hazards underscores the importance of adequate safety testing for these products, which thus far has been lacking.
- FDA-approved flavoring agents are prevalent in nicotine e-cig products and CBD/cannabis vape oil cartridges, but these additives were officially approved on the basis of safety tests for ingestion and topical application, not for inhalation as heated compounds. A 2018 study by University of Rochester scientists found that exposure to commonly used e-cigarette flavoring chemicals and liquids is toxic to white blood cells. 38
- Many flavoring compounds are toxic when heated and inhaled; cinnamon, vanilla and cream flavors among the most toxic. A recent report by Yale University researchers showed that mixing chemical flavoring agents is more dangerous than exposure to a single additive. 39 Moreover, some flavor additives interact with PG and PEG to form noxious acetal compounds. When heated and inhaled these inflammatory chemicals persist in the body for some time and irritate the lungs.
- A chemical called diacetyl is added to e-cigarettes and vape oil cartridges to simulate various buttery flavors, ranging from cream to vanilla and caramel. This particular compound is known to cause “popcorn lung,” a crippling and sometimes fatal respiratory illness. A shocking 2015 study of flavored e-cigarettes found that 39 out of 51 tested brands contained diacetyl. 40 It should be banned from use in vape oil.
The precautionary principle mandates that any thinning agent or flavor-enhancing chemical that has not been safety tested for heat and inhalation exposure should be prohibited as a cannabis oil additive.
- Girdhar, Madhuri et al. “Comparative assessment for hyperaccumulatory and phytoremediation capability of three wild weeds.” 3 Biotech vol. 4,6 (2014): 579-589. doi:10.1007/s13205-014-0194-0
- McPartland J.M., McKernan K.J. (2017) Contaminants of Concern in Cannabis: Microbes, Heavy Metals and Pesticides. In: Chandra S., Lata H., ElSohly M. (eds) Cannabis sativa L. - Botany and Biotechnology. Springer, Cham
- It’s worth noting that “vaporizing” can refer to two separate forms of administration. There are dry-herb vaporizers, which gently heat whole plant flower to temperatures below combustion to create a true vapor. These vaporizers may very well provide a safer form of inhalation than smoking. There are also vape pens, similar to e- cigarettes, which involve heating a cartridge filled with cannabis/CBD oil to very high temperatures (some have been recorded to achieve temperatures of 1000F) and inhaling the resulting smoke or vapor. These likely have a less safe profile, and likely have similar risks to smoking.
- Muthumalage, Thivanka, et al. “Inflammatory and Oxidative Responses Induced by Exposure to Commonly Used e-Cigarette Flavoring Chemicals and Flavored e-Liquids without Nicotine.” Frontiers in Physiology, 11 Jan. 2018, www.frontiersin.org/articles/10.3389/fphys.2017.01130/full.
- Eythropel, Hanno C, et al. “Formation of Flavorant–Propylene Glycol Adducts With Novel Toxicological Properties in Chemically Unstable E-Cigarette Liquids.” Oxford Academic, Oxford University Press, 18 Oct. 2018, http://academic.oup.com/ntr/advance-article/doi/10.1093/ntr/nty192/5134068.
- Allen, Joseph G, et al. “Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes.” National Institute of Environmental Health Sciences, Environmental Health Perspectives, 1 June 2016, http://ehp.niehs.nih.gov/doi/10.1289/ehp.1510185.