Precaution
WHO Precautionary Framework applied
to EMFs
See also WHO's recommendations on precaution in the 2007
Environmental Health Criteria Monograph and Factsheet. This seems to have replaced the Framework as the place where WHO's thinking on precaution is expressed, and the Framework is no longer available on WHO's web site.
Note: the WHO Precautionary Framework has been through several drafts and
has not yet been finalised or officially adopted. This page therefore
describes “work in progress” and should not be seen as a
statement of official WHO policy.
In October 2004 The World Health Organization (WHO) released an
updated draft of its “Framework to Develop Precautionary Measures
in Areas of Scientific Uncertainty.” The new draft is substantially
rewritten and expanded from the first draft issued in June of last
year. In particular, newly added Appendices B and C apply the framework
to ELF EMF and RF EMF as case studies.
THE FRAMEWORK
According to the draft document, the framework is intended
to
“guide WHO Member States in the development of their public
health policies and application of precautionary measures in the
face of scientific uncertainty.”
These measures are aimed at optimising the overall benefit for
society. The framework is not a mechanical formula, the WHO says,
but a process for clarifying and analysing key issues. Its basic
premise is that
“precaution should be viewed as an overarching philosophy
for risk management which is to be applied to all aspects of managing
an actual or potential health risk.”
The WHO expands the scope of factors to be considered in risk
assessment and management from solely scientific information to
social, political, and public health points of view as well. These
factors may include vulnerable populations, heightened concern for
the foetus and the child, inequities in the distribution of risk,
the total number of individuals exposed, and potential effects on
the quality of life.
The risk evaluation entails the traditional principles of science-based
risk assessment, e.g. weight of evidence, scientific uncertainties,
and underlying assumptions. In addition, however, the WHO’s
precautionary approach operates from a broader knowledge base. It
attempts to clarify what is not known, as well as what is uncertain.
WHO encourages the consideration of a broad range of options, not
restricted to specified statutory exposure limits. These are assessed
with either a cost-benefit or cost-effectiveness analysis. The depth
of the analysis will depend on the certainty and size of the risk,
and the WHO recommends that even very low-cost options be given
a rudimentary analysis. The options selected should provide the
best outcome for society and should be based upon balancing health
protection and cost. The process for making the selection must be
transparent to all stakeholders.
APPENDIX B: ELF EMF CASE STUDY
This seven-page appendix applies the precautionary framework to
exposure to ELF fields from the generation, transmission, and use
of electricity. It states that the IARC classification of magnetic
fields as “possibly carcinogenic” means that
“Under the WHO Precautionary Framework, [childhood leukaemia]
warrants a thorough consideration of precautionary measures including
detailed cost-benefit or cost-effectiveness analyses”
WHO examines and assesses the full range of options. With respect
to exposure limits, the report states:
“WHO believes exposure limits should be based on effects
conventionally regarded as established and are not an appropriate
mechanism for implementing precautionary approaches. Therefore
WHO does not recommend including exposure limits based on the
childhood leukaemia data as an option.”
Based on the facts that childhood leukaemia is a relatively rare
disease and only a small fraction of the population is exposed at
levels associated with a significantly increased risk, WHO states
that
“in view of these factors, and even after fully allowing
for the legitimate desire by society to err on the safe side, it
seems likely that only very low-cost measures will be justified.”
The report then lists examples of these low-cost measures. Its
full conclusions on the possible options are:
- exposure limits set at 0.4 µT or similar levels
seem unlikely to be justifiable. WHO considers that exposure
limits for EMF should continue to be based on science conventionally
regarded as “established”
- any measures involving changes to engineering practice
seem unlikely to be justifiable, unless they bring other
benefits as well, such as greater safety, or unless local
circumstances mean they of particularly low cost.
- it seems unlikely that a precautionary approach to EMF
alone could justify a change to distribution grounding practices,
but EMF should be considered alongside safety, reliability
and economics when changes are contemplated
- appliance manufacturers should investigate whether magnetic
fields could be reduced at low cost, and whether offering
consumer choice of low-field appliances could be an advantageous
marketing strategy
- enforcing existing wiring codes so as to reduce unintentional
ground currents must be sensible, but high costs in proactively
seeking out and identifying existing errors are unlikely
to be justifiable
- the costs of changes to planning regimes for high-voltage
power lines are dependent on national circumstances, and
no generalisation is possible. However, procedures may be
adopted which require efficient reduction of exposure for
each new project
- continued and enhanced research programmes are desirable
to remove uncertainty in the future
- communication to the public allowing informed decision
making seems eminently sensible and justifiable
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