Reply #63: NN....FWIW...I doubt that it was the re-start of the smoking that was...

[Sacajawea]

responsible. The damage to Peter Jennings's lung tissues began long, long ago when he took his first hit off a cig. There are hundreds (thousands?) of nasty chemicals in cigarette smoke and some of them probably attacked the DNA of the cells lining his respiratory tract. That's when the damage started. Day one. And then it's repeated over and over and over and over again, hundreds of thousands of times over the course of, say, 30 years. The damage has been done. And sometimes this repeated attacking of DNA causes its "structure" to be changed so that it no longer controls cells normally, but rather abnormally, causing them to become what we call "cancerous" and to grow in a wild and unrestrained manner. I don't know how long a time he went without smoking before resuming after 9/11, but I'd say that it's likely his cancer was lurking quietly long before 9/11, just waiting until it reached a critical mass (size) at which point some symptoms were manifested.

This is not gospel. It's just my recollection of what I learned long ago in college biology classes and my work in (recombinant DNA) research laboratories. I think the gist of what I said is correct.