Although I know that leading off with an apology is not recommended, in this case it seems appropriate to do so in this case – for having been somewhat erratic in the last few postings, and for having missed last week. The emergency response to Hurricane Sandy (now apparently renamed “Superstorm Sandy”) is winding down and things are a bit less hectic than they have been the last few weeks (last week was especially grueling). In any event, I thought it might be interesting this week to think about an oft-cited principle that is, I believe, not well-understood – the Precautionary Principle.
In a nutshell, the Precautionary Principle states that, if something is potentially harmful and it is not fully understood then we should assume it is harmful until it is proven otherwise. It is akin to the Hippocratic Oath – the part that admonishes physicians to “first do no harm.” But the Precautionary Principle is sort of one-sided as usually applied, and this is what I wanted to explore in this post.
Let’s start off with a rather simple one (and the one I know best) – exposure to radiation. First, there is no doubt that radiation can be harmful – we all know that it can cause cancer and, in higher doses, birth defects and radiation sickness. Most radiation scientists (myself included) would also agree that we do not yet know everything there is to know about radiation’s health effects. So a strict adherence to the Precautionary Principle would seem to suggest that we avoid all radiation exposure – that until we fully understand the impact of low-dose radiation we should simply avoid it altogether. But does eliminating ALL exposure to radiation really minimize our risks? I would suggest not.
Consider medical radiation, for example. When I worked in medical radiation safety we provided support for nuclear medicine, radiology, and radiation oncology. In each of these departments patients were exposed to radiation – which we know to be potentially harmful in sufficiently high doses – in apparent contradiction to the Precautionary Principle. Leaving aside for the moment the fact that a large fraction of physicians can’t quantify the risks of medical radiation to their patients, it’s reasonable to wonder about the possible longer-term health effects of this exposure. Are we putting patients at risk by prescribing these procedures? Should we outlaw medical radiation exposure in deference to the Precautionary Principle? Or is there more to consider?
Obviously the answer to the final question is “yes.” Consider – cancer takes decades to manifest itself, and the risk of developing cancer from radiation exposure is very low (the radiation from a single CT scan – among the highest-dose radiological procedures – carries with it a risk of less than 1/100 of 1%). When my son was x-rayed to try to diagnose the reason he was having problems breathing I accepted this risk gladly because not breathing is far more certain to be fatal, and very quickly fatal at that. My thought was that not breathing is also a health risk and it would be nice to keep my son alive in the short term. Similarly, x-rays can remove the need for exploratory surgery, can help physicians to diagnose disease, and so forth – all of the obvious risks from exposure to medical radiation are matched by obvious benefits. Few would debate the benefits of medical radiation exposure, if used responsibly.
So the Precautionary Principle would seem to be somewhat more complex than phrased above – we can’t simply ask ourselves if something has been proven safe beyond a reasonable doubt. We should also consider the risks of failing to take advantage of something that carries with it a benefit as well as a risk, and we should try to balance these against each other. Or to put it another way, lacking diagnostic information is a risk and, in some cases, this can be a greater risk than the radiation.
Let’s take a somewhat more difficult example – genetically modified organisms (GMOs). On the one hand, while we know a lot about these crops (and there are no indications I know of that links them to human health problems), we don’t know all there is to know. So a number of nations have decided that, in keeping with the Precautionary Principle, GMOs should simply not be sold or consumed within their borders – this way, if research some years or decades hence shows them to be harmful, at least humans were put at risk.
But what if a nation is starving? If genetically modified food is fed to the citizens then they are potentially put at risk – the risk is nebulous and unquantifiable, but it has not been shown to not exist. So many nations have decided that, according to the Precautionary Principle, GMOs should not be fed to even the starving. But withholding food – even genetically modified food – from starving people is certain to cause harm when they succumb to malnutrition and starvation. So what’s a leader to do? Feed his people with food that might make them ill years or decades hence, or withhold potentially risky food from his people? I would argue that, as with my son’s x-rays, the most reasonable course of action is to feed one’s people, even if the only available food is genetically modified. Someone who starves to death won’t live long enough to develop whatever problems might stem from eating genetically modified foods. It would seem to make sense – as with my son – to expose people to an indeterminate long-term risk in order to avert a certain death in the short term.
This makes me wonder if perhaps the Precautionary Principle should be re-formulated somewhat. There is a degree of philosophical purity in simply refusing to allow people to be exposed to a potential threat that cannot be quantified and that might carry a degree of risk. But we might not have the luxury of being philosophically pure, and this degree of purity simply doesn’t hold water when it leads to suffering and death. Weighing a long-term hypothetical risk against a short-term real risk is not easy – but weighing bodies in the street next week against hypothetical patients a few decades hence…that ought to be an easy choice.
Given all this, I’d suggest that the Precautionary Principle might need to be modified somewhat to be a bit less strict and one-sided – to encompass not only the exotic and hypothetical, but also the real and immediate needs of those who might be exposed. Instead of first doing NO harm, perhaps we should simply try to do as little harm as possible.