The Precautionary Principle


The precautionary principle is an environmental health risk management tool.  This principle, which first appeared in environmental policy documents in Europe during the late 1970s, serves as a guide in formulating policy for the protection of health and the environment.  The principle has been defined and interpreted in many different ways and therefore poses a real challenge to all who use it.





Today, this principle serves as a risk management tool, and is applied when there is a high level of scientific uncertainty.  The principle calls for taking steps in cases of potential risk, without waiting for the final results of scientific research.










The precautionary principle may be found in a broad range of international treaties, where a variety of definitions may be seen.  Moreover, the principle has been discussed and incorporated into the legislation (in a few countries, including Israel and Switzerland), and appears in legal rulings in a number of countries.  These rulings are influenced by the social and political values in those countries.  Consequently there are vast differences in approach to the principle and its application among different countries and agencies.


In its most stringent wording, the precautionary principle is interpreted as requiring unequivocal proof of the safety of a particular technology before it is made available for general use.  Another interpretation appears in the Rio Declaration on Environment and Development, which favors the application of a cost-benefit analysis before the decision to apply a technology.  Some believe that to implement the precautionary principle some measures (undefined) must be taken, even if the causal relationship between exposure and a harmful effect has not been proven.


In 2000 the European Union published a leading document on the precautionary principle, including guidelines that would enable the implementation of the principle, with 'political transparency', based on a scientific risk evaluation, thus cautioning against arbitrary application of the principle.  The document states that the precautionary principle may be invoked as a 'basis for action in the event that scientific data do not permit a complete evaluation of risk…but can never justify taking protective measures while ignoring available scientific evidence.'


The decision to act according to the precautionary principle is a policy-making decision.  This document does not detail the amount of evidence required as a basis for applying the principle, nor how it should be applied.  The spirit of the document requires taking reasonable measures appropriate to the required level of protection, while acknowledging that 'zero risk' is rarely to be found.  Moreover, the steps taken should be adapted to the existing policy regarding similar topics and similar sources of exposure (e.g. sources of radiation with comparable attributes).  All this should also take into account cost-benefit considerations, which may be changed or updated in accordance with new scientific evidence.


Application of the precautionary principle to non-ionizing radiation is secured by law in Israel.  The definition of the precautionary principle in Israeli legislation appears in the explanatory notes (Hebrew) of the preamble to the Non Ionizing radiation Law, as follows:


"According to this principle, reasonable precautionary measures should be taken to minimize the 'risk', even in the absence of sufficient scientific evidence of harmful health effects from a specific agent, without awaiting the completion of  studies designed to reduce the uncertainty regarding the existence of said health risks."


In general, there is a consensus in Israel among most of the relevant bodies in applying the precautionary principle while giving due consideration to reasonable costs, in the attempt to reduce exposure to the minimum necessary to ensure efficient and safe use of a given technology.



  • The application of the precautionary principle to non-ionizing radiation is vital.

  • Exposure to this radiation is an integral part of the daily life of the general population.

  • There is scientific uncertainty regarding the health effects of exposure to this radiation.

  • The public is concerned about exposure to these sources of radiation.