Why is there a warning about exposure to cannabis smoke?

Cannabis (marijuana) smoke has been placed on the Proposition 65 list due to its potential to cause developmental harm and cancer. Pregnant individuals who smoke cannabis or are heavily exposed to cannabis smoke can put their child’s development at risk, affecting birth weight, behavior, and learning ability. Furthermore, exposure to cannabis smoke may increase the risk of cancer.

Cannabis smoke is produced when the dried leaves, flowers, stems, seeds, and resins of cannabis plants are burned. It contains a myriad of chemicals, several of which are listed on Proposition 65. These chemicals include THC (delta-9-tetrahydrocannabinol), which can impact the child’s behavior, learning ability, and vulnerability to drug addiction if the mother is exposed during pregnancy.

Additionally, other harmful chemicals present in cannabis smoke, such as benzene, benzo[a]pyrene, 1,3-butadiene, cadmium, carbon monoxide, hexavalent chromium, formaldehyde, lead, mercury, and nickel, are known to cause cancer and reproductive harm. Many of these same chemicals are also found in tobacco smoke, which is listed on Proposition 65 due to its association with cancer, birth defects, and reproductive harm. Businesses are required by Proposition 65 to assess whether they need to provide warnings about significant exposure to listed chemicals.