NOT TRUE. I smoked it for years in my early life. I am 63 and just had an oxygen saturation test measuring 97%. I would say that trumps your OPINION.
As previously stated, I would do it now, but for the WOD penalties. I did smoke an Acid cigar last night, and washed it down with two fingers of Glenmorangie 18!
I am happy that at this time you have not apparently experienced symptoms. I still think saturating ones lungs w/ smoke and holding it is a very dangerous/stupid thing to do. I would never do it again. But, when I was young and foolish........