June 20, 2009 – California NORML testified at the EPA hearings leading to the decision to categorize marijuana smoke, along with aspirin, potato chips and french fries as a potential carcinogen.
The Cal EPA did NOT claim that THC itself is carcinogenic. They were looking at the smoke from the burned leaf, which contains hundreds of other chemicals produced by combusted hydrocarbons, just like tobacco. There’s a long list of known carcinogens in MJ smoke – benzene, acetaldehyde, benzo(a)pyrene, etc. Whether the cancer risk from these chemicals is appreciable is another question, as the largest and best-controlled studies have failed to detect one.
Nonetheless, a number of smaller-scale studies have reported a statistical link between marijuana smoking and throat cancer as well as other smoking-related cancers. Even though these studies have not been definitively confirmed, this is enough to convict in the minds of environmental regulators.
Interested parties can read the full report at: