Electromagnetic Fields and the Precautionary Principle

While for substances that may be detrimental to health if incorporated through the skin, or by inhalation or ingestion precautionary procedures have been developed in the past decades that are applied in a transparent and standardised way by health authorities, public health agencies and international organisations in order to protect the public from a potential health hazard, no such procedures have been applied so far on a broader scale for electric, magnetic, and electromagnetic fields (EMF). In some countries (e.g. Italy and Switzerland) aspects of precaution have been entered into decisions about guideline levels limiting exposure to EMFs, however, these approaches have not been appreciated as major steps towards a change of paradigm in the derivation of exposure standards. “A cautionary policy for EMF should be adopted only with great care and deliberation. A principal requirement is that such policies be adopted in such a way not to undermine scientific assessment of risk and science-based exposure limits.” (WHO International EMF Project, Geneva, Oct 2003). This statements neglects a number of essential problems inherent in the process of the derivation of exposure limits that have since long been considered by other WHO bodies. An example are the introductory remarks to the WHO Air Quality Guidelines for Europe: ”To produce a guideline with a high probability of offering absolute safety, one would need a detailed knowledge of dose–response relationships in individuals in relation to all sources of exposure, the types of toxic effect elicited by specific pollutants or their mixtures, the existence or nonexistence of ‘thresholds’ for specified toxic effects, the significance of interactions, and the variation in sensitivity and exposure levels within the human population. Such comprehensive and conclusive data on environmental contaminants are generally unavailable. Very often the relevant data are scarce and the quantitative relationships uncertain. Scientific judgement and consensus therefore play an important role in establishing guidance that can be used to indicate acceptable levels of population exposure. Value judgements are needed and the use of subjective terms such as ‘adverse effects’ and ‘sufficient evidence’ is unavoidable.” (WHO 2000). It must be emphasised that neither risk assessment nor derivation of exposure limits can be based purely on scientific evidence. As underlined by the statement above value judgements are unavoidable as are decisions about how to deal with scientific uncertainties and which margin of safety is acceptable. In order to make the process transparent it is necessary to differentiate between statements that are based on a scientific evaluation (i.e. that are based on a thorough and balanced consideration of scientific evidence) and statements that are based on value judgements (e.g. introduction of safety factors).