Hardly a week goes by when some influential statement does not invoke the precautionary principle as an excuse for anti-vaping policy. This is always an error because the precautionary principle does not offer any argument in favor of restricting vaping or vapor products.
The precautionary principle gained prominence at the 1992 U.N. Conference on Environment and Development in Rio de Janeiro. It is not precisely defined, and there are countless somewhat contradictory proposed definitions. But the valid candidate definitions basically say that when a potential action has irreversible impacts (which more precisely means changes that cannot practically be reversed for a very long time), and there is an apparent risk of serious harms, those who want to create those changes are obliged to first provide strong evidence that serious harm will not result. This applies especially to “right-tail” risks — those with low apparent probability but extremely high costs.
The first thing to understand about the precautionary principle is that it is just a political position, and even though it is (when interpreted correctly) a compelling position, it is still not divine law. The second thing to understand is it is a statement about irreversibility and burdens of proof.
This principle applies to many environmental issues, but to almost no non-environmental public health issues. Those who misuse the phrase seems to be fixated on the the “caution” part of the word “precautionary,” unaware that the entire phrase means something specific. They further misinterpret “caution” to mean paralysis: “avoid any action that might have a downside.” Since every action involves risk, this faulty interpretation of the precautionary principle can be used as a disingenuous attack on any action someone personally disapproves of.
The principle is a response to the tendency of environmental policy to force those who are concerned about the impacts of an irreversible change — such as damming a river, clear-cutting a forest or releasing a persistent chemical into the environment — to prove that it would be harmful. If the burden of proof goes in that direction, and environmental protection advocates cannot provide compelling evidence of serious harm (which is often impossible), the action is allowed. Indeed, even if compelling evidence exists, the action often goes forward before the evidence can be gathered.
The precautionary principle is a reasonable backlash against just allowing manufacturers, energy companies and governments to create pollution or risks. Many examples are obvious. Some are less so, like the case of microbeads — extremely tiny bits of long-lived plastic, ingredients in many cosmetics — that accumulate in lakes and rivers. They are belatedly being banned in some jurisdictions, but is reasonable to say that manufacturers should not have been allowed to just start introducing those chemicals into the environment in the first place.
By now, you may be thinking “this does not seem to have any resemblance to vaping or other behaviors.” Exactly. First, the burden of proof that there is no huge downside has been adequately met. There was evidence from the start that there was no apparent major risk, and a decade of vaping rules out most right-tail risk scenarios.
Second, vaping exists and it is not going away. The precautionary principle was arguably relevant when FDA prevented e-cigarettes from being introduced in the 1990s (but see the next point), and perhaps even when it tried to throttle their import in the 2000s. But now there cannot be any issue of heading off the irreversible establishment of the products (even setting aside the low risk).
Third, product availability does not create an irreversible change like building a dam or polluting an ecosystem with persistent chemicals. Even if the product were to prove harmful, the harm lasts only as long as the product is used. If something bad shows up, the harm can be ended by banning the product. Were it not for this, every FDA approval of a new pharmaceutical would run afoul of the precautionary principle.
For this reason, there is no precautionary principle argument against the iQOS or other heat-not-burn products. Yes they are fairly novel and their establishment could be prevented (at least until their popularity in other jurisdictions created irresistible momentum). Perhaps someone believes, despite the extensive studies of the product chemistry, there is serious right-tail risk potential. But there is no irreversibility. If something goes wrong, a ban can be imposed. Indeed, unlike with e-cigarettes, for which it would be impossible to eliminate a cottage-industry black market, if major manufacturers remove their heat-not-burn products from a market, the category is effectively eliminated.
In short, there is no precautionary principle argument against low-risk tobacco products. The burden of proof that the principle demands has been quite thoroughly met. There are no irreversible actions that might cause lingering damage, even if a concern about a right-tail risk turned out to be valid. Indeed, the only apparent irreversibility in sight is that once people learn the truth — that vaping and other smoke-free products pose little or no risk — there is no taking away that knowledge. That indeed may be what many anti-vaping activists are most worried about, but unless they are willing to say that out loud and argue accurate knowledge is a serious harm, they have no business appealing to the precautionary principle.