Health Canada is doing some studies and their basic conclusion is that the health effects of smoking contraband are the same as smoking regular cigarettes. There are some particular cases where the manufacturing processes are different and inadequate, have special flaws, have all kinds of other contaminants in the products. The biggest health problem is the low price which encourages kids to get addicted and which keeps smokers smoking. So there are really huge negative health effects from contraband.
On December 10th, 2013. See this statement in context.