Beware The “Precautionary Principle”

Photo of Gregory H. Smith
Gregory H. Smith
Director & Chair, Administrative Law Department and Managing Director of State Capital Office
December 18, 2000

State Representative Derek Owen of Hopkinton has introduced a bill that would make it State policy to use the so-called “precautionary principle” when determining the safety of using products and technologies. Although aimed specifically at the land application of biosolids (treated sewage sludge), the proposal will have significantly broader ramifications for environmental laws, if adopted.

The precautionary principle may be understood as a way of decision-making, but as it is being proposed, it would be much more than that. It would become the basis for modifying and expanding existing environmental laws and regulations. This proposal relies on a plainly false premise: that the existing framework of regulatory control isn’t working. This just isn’t true.

Today we have a science-driven regulatory system based, in large part, on the scientific process of risk assessments. Risk assessments are science-based estimates of the human health risk faced by a population exposed to a particular substance, activity, lifestyle or natural phenomenon. Risk assessment is a well-established, reliable method of hazard assessment, using peer reviewed, state-of-the-art information, and includes consideration of potential consequences for human health, and the natural environment.

In contrast to the well-established methodology of risk assessment, the “precautionary principle” proposal ignores sound science and elevates doubt, i.e., any suspicion of potential risk or harm, to a central role in decision-making. As applied, this approach is unreasoned. There are at least three reasons why the “precautionary principle” itself presents risks to human health and the environment.

First, as a society, we should focus on the known or probable causes of harm. If we were to adopt the precautionary approach, there would be an irresistible tendency to devote less time, money, and fewer resources to evaluate and manage the real public health problems which confront society.

Decision-makers should continue to use risk assessments to prioritize public health and environmental risk management. That is, risk-based priorities should be identified using the best possible science to assure that significant resources are allocated to management of the most important health and environmental threats. We, as a society, should avoid the distraction of purely hypothetical threats.

Second, if we did adopt the “precautionary principle” and focus on hypothetical risks, we would shift public policy development away from the world of science and reason, and enter the world of ideology. This ideological framework would ignore science and reject technological advancements. Yet technological advance is, itself, producing advances in human health and environmental protection while elevating societies’ standard of living.

Lastly, the “precautionary principle” ignores reality. Human existence necessarily involves risk. There is absolutely no way of avoiding all risk in our lives. There is no safe harbor of “harmlessness” even if we want there to be one. The advance of human progress has been sustained by our scientific understanding of risk, not by rigid ideological assumptions about the risks of progress.

Risk assessments combine information on the level of exposure to a substance and its observed toxicity to characterize what is likely to happen in humans who may be exposed to it. Acceptable risk thresholds are typically measured in parts per million, parts per billion, or parts per trillion. But to underscore the conservative nature of risk assessments, here are some concentration analogies for your consideration. Regulatory levels are set several orders of magnitude lower than the analyses predict is safe, to provide an extra margin of safety:

  • One part per million is 1 inch in 16 miles.
  • One part per billion is one second in 32 years.
  • One part per trillion is one square inch in 250 square miles.
  • One part per quadrillion is one human hair out of all the hair on all the heads of all the people in the world. (Source: Reporting on Risk, Produced by Foundation for American Communications and National Sea Grant College Program, 1995)

Since Rep. Owen’s bill is being proposed within the context of the biosolids debate, let’s consider the scientific basis for setting the current standards. In developing risk assessments on the ingestion of substances in biosolids (which can be applied to farm field), the EPA used the following scenario:

  • A teenager who is an avid gardener and plants his/her own vegetables;
  • One who fertilizes exclusively with biosolids and who obtains 50% of vegetables from a biosolid-fertilized garden; and
  • One who maintains this pattern for 50 years.

The levels considered safe for reuse of biosolids rely on such conservative assessments as this. Clearly, EPA’s risk assessment methodology provides for a very significant margin of safety in order to protect even the most vulnerable members of our society, and accordingly more typical exposure is even less of a concern.