Scientific American has published a review of the thirdhand smoke issue, including an interview with one of the authors of the study which brought the issue to national attention. In the article, that anti-smoking researcher warns that even when not actively smoking, smokers are contaminated and emit toxins that are hazardous to children. He also suggests that thirdhand smoke can result in lead poisoning among infants because of the presence of lead in tobacco smoke.
The article quotes the researcher as stating, in response to the question "Why is thirdhand smoke dangerous?": "The 2006 surgeon general's report says there is no risk-free level of tobacco exposure. There are 250 poisonous toxins found in cigarette smoke. One such substance is lead. Very good studies show that tiny levels of exposure are associated with diminished IQ."
It also quotes the researcher as stating: "Smokers themselves are also contaminated…smokers actually emit toxins [from clothing and hair]."
The Rest of the Story
While the claims made in this article make for interesting reading, they are not science. There simply isn't scientific support behind the assertions made by this researcher. In fact, Dr. Stanton Glantz himself acknowledges in the article that there is no scientific evidence to document that thirdhand smoke is hazardous to children and infants. According to the article, Dr. Glantz "is not aware of any studies directly linking third-hand smoke to disease."
So if there isn't scientific evidence linking thirdhand smoke with disease, then how can the anti-smoking researcher claim that thirdhand smoke causes lead poisoning?
The answer is that you don't need science behind you to make health claims in the tobacco control movement. You can make any claim you want and rest assured that virtually no one within the tobacco control movement is going to publicly question your statement. Sure, there may be some private discussions in which researchers whisper between themselves how unsupported the claim is. But there is no danger of the dissenting opinions becoming public, because dissent on issues like this is simply not allowed in this religious-like movement.
I am certainly not aware of any evidence that the levels of lead in household dust in homes with a smoker are high enough to cause lead poisoning in infants. For that matter, I am not aware of any evidence that the toxins in thirdhand smoke are ingested or inhaled to the level necessary to actually cause harm to children.
To be sure, speculation is reasonable. But if you're going to speculate, you need to make it clear that what you are doing is speculating. The Pediatrics article and this interview are not what I would characterize as speculation. Both make definitive health claims: that thirdhand smoke causes health damage to infants and children. And to the best of my knowledge, these health claims are not supported by any actual evidence.
It also seems rather obnoxious to call smokers "contaminated" and emphasize that they are "emitting toxins," without having any evidence that such "toxins" are actually causing health damage to nonsmokers. I may well have detectable levels of "toxins" from the smoke to which I am exposed from my pellet stove, but it would not be fair to say that I am contaminated and emitting toxins. (I did fall into a pile of metal hydroxide sludge once and I admit that at that moment I was contaminated.)
I also don't understand exactly what the point is. Is it to cast smokers as social outcasts who should be spurned from society and not allowed to have any contact with "the rest of us?" Is it to try to stimulate efforts to ban smokers from being child care providers or teachers? Because if it is true that smokers are contaminated and emitting toxins, then we certainly wouldn't want our children to be exposed to those toxins in day care centers or schools.
Another curious statement in the article is that "Studies in rats suggest that tobacco toxin exposure is the leading cause of sudden infant death syndrome (SIDS)." How could studies in rats possibly indicate the degree to which tobacco exposure is causing SIDS in humans? One would certainly need epidemiologic studies, not merely rat studies, to determine the extent to which tobacco smoke exposure is causing SIDS in humans.
While the article concludes by suggesting that the thirdhand smoke danger points to the need for all smokers to quit, I am afraid that the hysterical nature of the thirdhand smoke claims may actually do the opposite. It may convince many smokers that the anti-smoking folks are fanatics and that they should stop listening to this hysteria. It may also undermine the public's appreciation of the hazards of secondhand smoke and convince many smokers not to bother smoking outside of the home (since their children would be damaged anyway by the thirdhand smoke).
One final note. We've known about the offgassing of constituents from tobacco smoke that has absorbed on surfaces for a long time. What scientific evidence is new such that it would warrant a public education campaign about thirdhand smoke?
The most interesting aspect of this story to me is not that an anti-smoking researcher would make unsubstantiated and somewhat hysterical assertions like these, but that almost no one within the movement is willing to publicly challenge these assertions.