Just FYI technically marijuana is much safer than cigarettes. Marijuana does not cause cancer, does not cause emphysema, and does not cause tar buildup in the lungs. When you burn marijuana the 'bad' tar is left where it's burnt, not in the smoke -- what you find in the smoke is resin which will build up in the lungs, but your lungs do a pretty good job of getting it out. Cigarette smoke however clogs small airways in your lungs and make it harder to transfer oxygen and co2. The marijuana resin accumulates in larger air-passageways so it doesn't cause nearly as big of a problem even with habitual (everyday) use.