What's in Your Rolling Paper?
Can cannabis rolling papers make people sick?
Until recently, most brands and consumers didn’t think twice about rolling paper safety. However, the reality behind cannabis packaging contamination might forever change their perspective.
This article investigates brand-new research exposing heavy metal adulteration in rolling papers and reveals potential solutions for brands and consumers.
Contaminated Rolling Papers and Compliance Failures
Rolling paper and packaging contamination is an issue the cannabis industry did not foresee or regulate against.
State lawmakers require cannabis brands to submit products for safety testing, ensuring that formulas and flower are free from common contaminants. However, cannabis packaging, including rolling papers, bottles, and droppers, isn’t subject to the same compliance rules.
Additionally, not all states require finished goods testing. Many assume that if a batch of cannabis flower passes a heavy metal test, subsequent products, like prerolls, should also be safe. However, prior rolling paper experiments and analysis of tobacco cigarettes say otherwise.
In 2020, researchers found that California prerolls made from bud that previously passed heavy metal screening contained unsafe levels. In fact, 91 of 101 papers, cones, and wraps failed heavy metal testing. Tobacco cigarette experiments found similar impurities, including heavy metals along with many other toxic elements in tipping papers, the part that touches the person’s lips.
These reports strongly signaled the possibility that contaminated rolling papers and prerolls could regularly pass through safety screening processes and reach consumers.
2024 Study Finds Heavy Metals in Cannabis Rolling Papers
Researchers from Michigan’s Lake Superior State University wanted to quantify the extent of heavy metal contamination in commercial rolling papers. In April 2024, they published the industry’s first peer-reviewed paper on the topic.
The team analyzed 53 commercially available rolling papers for 26 potentially toxic heavy metals and compared the concentrations to regulatory safety limits from various US states and Canada.
Results and consumer impacts
The study found that cannabis rolling papers frequently contained heavy metals, which could pose health risks when smoked in excess. To make matters worse, most people fill their joints halfway, increasing their toxic exposure.
The most common heavy metals in rolling paper included:
Other problematic elements included:
- Silver
- Nickel
- Cobalt
- Molybdenum
- Antimony
Additionally, the study found varied levels of arsenic, cadmium, mercury, and lead. Some products contained unsafe, non-compliant levels of these highly toxic heavy metals.
- Lead had the greatest variation, with several samples exceeding California’s lead action level of 0.5 μg per gram under Prop 65.
- Four samples contained arsenic at 0.2 μg or higher per gram, enough to surpass acceptable limits in some jurisdictions.
All heavy metals, including arsenic, cobalt, and copper, can pose health risks. The risk is significantly elevated for people who smoke about five grams (approximately five joints) daily, according to the study.
Copper is the most prominent contaminant
The rolling paper study found that copper occurred at the most elevated levels of all 26 heavy metals.
- Around 25% of rolling papers exceeded the recommended levels of copper for inhaled pharmaceuticals. In rare cases, the quantity significantly exceeded the recommended daily exposure limits.
- Regularly using these rolling papers might result in exposures as high as 4.5 to 11 times the maximum limit.
How Do Rolling Papers Become Contaminated?
Cannabis rolling papers regularly contain heavy metals for several reasons, according to the Michigan research team.
One reason is that rolling papers are typically made from plant fibers, including wood pulp, flax, hemp, rice straw, and other extracts like cellulose. These highly absorbent materials easily soak up heavy metals and pesticides from the surrounding environment.
Rolling papers made from recycled materials pose an even greater contamination risk because the process requires additives, including lead, arsenic, cadmium, chromium, and zinc, to improve the surface texture and color,
Manufacturing issues, including the use of ink and pigments in tipping paper cones, are another source of rolling paper contamination.
- Blue, green, purple, and black rolling cones had the highest copper concentrations (up to 30 μg per gram) in the study.
- Yellow and red cones lacked copper but contained other heavy metal elements like titanium and strontium.
- Metallic-colored tip materials in the gold—and silver-tipped cones were composed of polyethylene terephthalate (PETE). This explains why some samples contained antimony, a common catalyst and contaminant in PETE production.
Should Consumers Avoid Cannabis Rolling Papers?
Should consumers avoid cannabis prerolls and rolling papers due to heavy metal contamination?
The 2024 Michigan study did not directly suggest that people avoid rolling papers entirely. However, the findings indicate concern over the potential health risks for frequent users and suggest that more research and regulatory review are needed to ensure consumer safety.
How Can Rolling Paper Manufacturers Reduce Heavy Metal Contamination?
The Michigan research team emphasized the need for more regulation, oversight, and changes in manufacturing practices to reduce rolling paper contamination. Specifically, manufacturers can take the following targeted actions to prevent heavy metal buildup:
Eliminate Copper-Based Inks: Manufacturers should consider eliminating copper-containing inks to reduce the median copper concentration in rolling papers substantially.
Replace PETE Tips: Replacing PETE tips with cleaner materials like plain paper could reduce potential health risks.
Avoid Hazardous Additives: Avoid using additives that contribute to heavy metal contamination, such as particular dyes and pigments that may contain hazardous metals.
Rigorous Testing: Implement more rigorous cannabis testing protocols for heavy metals and other contaminants in rolling papers, inks, and other materials used in manufacturing.
Product Design Review: Evaluating product designs to minimize unnecessary use of potentially harmful materials and exploring alternatives that might reduce health risks.
Educational Efforts: Informing consumers about the potential risks associated with certain types of rolling papers, especially those that may include metals like copper and chromium at hazardous levels.
What Are the Health Risks of Heavy Metal Exposure?
Heavy metals are toxic and carcinogenic, and consistently smoking compromised rolling papers may pose long-term health risks.
- Copper toxicity (getting too much copper regularly) can cause liver damage, abdominal pain, cramps, nausea, diarrhea, and vomiting.
- Even low levels of lead in the blood can cause health problems, like increased blood pressure, kidney and brain problems, infertility, and impotence.
- Inhaling antimony can agitate the skin and eyes. Long-term exposure can cause respiratory effects, such as inflammation of the lungs, chronic bronchitis, and chronic emphysema.
Why Is Testing Rolling Papers and Pre-rolls Important?
Most states do not have comprehensive testing requirements for cannabis packaging and finished goods. Thus, many brands bypass this critical step before going to market.
However, all brands, whether required or not, are responsible for delivering safe and clean products to consumers.
Fortunately, many manufacturers test their cannabis formulas and finished goods for harmful chemicals, publishing the results in a transparent certificate of analysis (COA). Testing rolling papers offers customers peace of mind and provides a value-added brand differentiator in an increasingly crowded market.
Businesses that skip third-party laboratory testing miss out on a vital opportunity to build trust and gain a loyal following.
Bottom Line
The rolling papers study showed that cannabis product design and manufacturing practices can significantly increase exposure to heavy metals. The everyday use of copper-based printing inks and PETE tips is especially concerning and can increase health risks in heavy smokers. Rigorous lab testing is essential to close the cannabis industry’s quality gap.
We test rolling papers for clients to help them identify potential contaminants and their supply chain source. Contact us today to ensure your papers and pre-rolls are safe.
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