While many people are concerned by the quality of ingredients that are included in their cannabis products, most overlook the possibility of compounds leaching from the packaging and into the cannabis. This is why certificates of analysis (COAs) that indicate the presence or absence of contaminants in cannabis products have become the backbone of quality standards in the industry. However, packaging can pose a threat to the safety of cannabis consumables.
In Germany, lead contaminant 4-methylbenzophenone, which is found in printing ink, slipped from the outside of the cardboard box and into muesli cereal. 
In early 2019, California had to take their cannabis testing a notch higher when high levels of lead were discovered during the testing of several disposable vape cartridges.
In fact, it’s been argued that it’s not about whether the packaging components will leak into the product but how much will leak. This is because most packaging materials are not inert. And if that’s the case, then the concern becomes a toxicity risk.
Plastic packaging is normal in many industries. A common leachable found in plastic is bisphenol A, or BPA, although many manufacturers portray their products as BPA-free (the question then should be what replaced BPA). Phthalates, which are used to make plastics such as polyvinylchloride more pliable, are also a concern. 
Glass is considered a safer alternative for packaging because it’s relatively inert. However, many glass jars used in cannabis dispensaries have a cap with a rubber seal which presents another problem. Rubber has the risk of containing high amounts of N-nitrosamines, which are equally as carcinogenic. 
Another challenge that arises is the red tape—especially as applies to cannabis packaging in Canada. Cannabis packaging must adhere to the following standards:
- Opaque packaging with uniform color
- Child resistant
- Must not appeal to children
- Must contain warning on risks associated with long-term cannabis use
- Must have a security seal
- Must have a standardized cannabis symbol
Lastly, the issue of eco-friendliness comes up. In modern society, where consumers are keen on environmental sustainability, cannabis businesses are finding that they must adjust to customer expectations. Eco-friendly packaging may come at a higher cost compared to regular packaging. In spite of this, the industry as a whole is adapting to sustainable packaging.
What is the solution?
BPA-free plastic packaging is becoming the standard in cannabis packaging, at least where plastics are involved. Perhaps polymers derived from hemp raffinate and waste material can help supplant plastics derived from fossil fuels. Re-packing your products in amber glass jars can be viable if you’re planning to store the product long-term.
When it comes to rubber contamination, a rubber bath can be applied to rinse away problematic leachables in rubber.
Ink leaching can be reduced through the use of cross-linked ink components. Decreased-migration inks are another option.  Droppers should be etched with dosing graduations and not printed on, as the ink can dissolve in terpenes.
It’s worth pointing out the leaching from packaging is likely proportional to a product’s time spent in said packaging, and the product’s chemistry, such as its terpene content. Ultimately, all potential solutions come at a significant cost. Will cannabis consumers be willing to pay more for “safer packaging” with less chances of contamination? Will you?
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Everts S. “Chemicals Leach from Packaging.” Chemical & Engineering News, vol.87, no.35, 2009, p.11-15. Journal Impact Factor 1.126. Times Cited: 6 (ResearchGate)