Heavy users could be exposed to high levels of copper, chromium, and vanadium

Cannabis users may be inhaling unsafe levels of heavy metals as rolling papers burn, according to a new study (ACS Omega 2024, DOI: 10.1021/acsomega.3c09580). Some papers used to prepare joints, particularly papers that contain dyes or have metallic-colored tips, contain enough copper or chromium to potentially harm frequent cannabis users. “Most consumers appear to think that someone in the government must regulate this,” says Derek Wright, an environmental scientist at Lake Superior State University who coauthored the study. But in the US, both cannabis’s legal status and regulations on rolling papers vary by state. And though some states limit metal content in cannabis flower, they usually don’t regulate metals in the wrappers, even when the papers are used in prerolled joints and other ready-to-smoke products. ....