Ah the famous picture of a guy who's lower jaw just fell off after he kept drinking this.
Similarly well known 'radium girls'.
Horrific cases.

They all seem sealed with a black varnish, and I have personally never held one or been able to look at the bowl or stem to see if they're coated as well.

Naturally, both the stem and the bowl would lightly cake with carbon over time, 5-6 bowls before it's on everything evenly.

Find one and be the hypothesis lol.

I'll stick to briar

The dust is actually fine needles that cause chronic inflammation in lungs, which triggers cancer. But this can happen with any fibres. Lately everyone is using carbon fiber and it's as bad as asbestos.

Fun Fact!

Pipe Tobacco is almost never inhaled by pipe smokers if they never smoked cigarettes beforehand, and pipe enthusiasts are more anal about natural tobacco and unnatural additives.

This is one of the difficult parts of reading up on lung cancers between both groups. I couldn't find any studies pointing directly at "pipe and only pipe smoking", as the population pools for testing people dwindled rather quickly by the late 1980's since pipe smoking was mostly gone outside of hobbyists.

I'd pair this up with vaping/snus in the harm-reduction camp if that's true. I wouldn't consider any type of smoke entering your body as entirely harm-free... or vapor, or nicotine for that matter.

Wait til you learn about what they used to put in cigarette filters

We still do.