Third-hand smoke definitely exists...it is the stink you smell on the skin, hair, and clothes of people who smoke, and in the rooms they smoked in due to contamination of sofas, carpet, walls, etc.
The main health concern is for infants, who breathe in more dust and residues in homes since they are closer to the floor, and so are more likely than adults to be affected by third-hand smoke. Also, infants are more susceptible than adults to respiratory troubles and developmental harm caused by carcinogens and other chemicals.
What is third-hand smoke? Is it hazardous?: Scientific American
The danger of a carcinogen is a function of the carcinogen's strength, exposure time, and the developmental stage of the person. I doubt most infants are given a lot of coffee, chocolate, pepper, and peanut butter, so the negative impact of third-hand smoke on infants whose parents smoke could be much greater compared to the impact of carcinogens in those foods.
On what basis do you assume that the harm of third-hand smoke is inconsequential compared to the harm of other carcinogens you list? And does the fact that an infant could be murdered mean we shouldn't care about environmental pollutants she is exposed to?
Second-hand smoke (the smoke inhaled by children as parents smoke around them) is much more of a concern than third-hand smoke, but this doesn't mean the negative effect of third-hand smoke on children or adults is negligible and should be ignored or minimized by claiming research into this topic is "agenda-terror." I find it odd that you both feel a certain topic should be off limits to scientists who are trying to understand more fully the negative impacts of smoking on people who are involuntarily exposed.
Here's a brand of cigarette to add to the list:
The Candy Cigarette. Hook your customers on the habit while they're young!
