The authors note that many of the samples purchased for the research had been colored to make them more appealing to consumers than standard white rolling papers. The researchers analyzed the various samples for the presence of 26 different compounds that could cause negative health effects, most of which are heavy metals. The team of researchers used standard chemical analysis tests to measure the quantities of the compounds in the rolling papers, including tests that burned the products to determine the amount of heavy metals in the smoke that would enter the user’s lungs.

The results of the analyses varied widely among the different products tested. Some samples had low levels of heavy metals, while others contained very high levels that could pose a danger to consumers who use them frequently. Elevated levels of copper were found in many colored samples, particularly blue and green cones, presumably from the pigments used to produce the bright hues.  Other samples had elevated levels of the heavy metals chromium and vanadium. Some cones contained high amounts of antimony, which researchers said is likely because the element is used as a catalyst to produce the polyethylene terephthalate (PET) in their tips.

The research highlights a potential health risk that many consumers may not be aware of. Derek Wright, an environmental scientist at Lake Superior State University and co-author of the study, said that most people who use rolling papers assume they are safe. “Most consumers appear to think that someone in the government must regulate this,” Wright told Chemical and Engineering News. The researchers note that it would not be difficult for rolling paper and cone manufacturers to remove heavy metals during production.

Ideally, many of the compounds can be eliminated from the manufacturing process entirely. Doing so, the authors of the study note, would reduce the risks faced by consumers. “None of these components are necessary,” Wright noted. Wright added that reducing the risks associated with cannabis use is particularly important for medical marijuana patients. “We have an at-risk population—so people that are already potentially sick with maybe serious diseases like cancer—using marijuana for pain management, and then potentially exposing themselves to things that could be conceivably hazardous,” said Wright.

The researchers recommended that state lawmakers and other policymakers take note of the study’s findings and implement regulations to compel the manufacturers of rolling papers and cones to reduce the levels of heavy metals in their products.  “Additional efforts by state regulatory agencies to reach a consensus on limits to toxic elements in cannabis and smoking papers are warranted based on our findings, as is additional research to determine exposures based on realistic use patterns,” the authors of the study wrote in their conclusion.

Daniel Curtis, an analytical and atmospheric chemist at California State University, Fullerton, who was not involved in the research, said that the study is valuable because it is the first time that an examination of the heavy metals content of rolling papers specifically designed for cannabis use has been undertaken. “This is a really important study,” Curtis said, adding that he believes that additional research should be conducted to determine how much of the heavy metals in rolling papers is being incorporated into smoke as they are used.

“We know cannabis use is increasing,” Curtis said. “If we can identify where potentially toxic chemicals are coming from, we can eventually use that information to make a safer product.” Read less