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World Health Organization Environmental Health Criteria 137 - Electromagnetic Fields (300 Hz to 300 GHz) (1993)

Preview: Learn how WHO Environmental Health Criteria 137 documented the 1993 international assessment of electromagnetic fields and why it is now a historical rather than current compliance reference.

World Health Organization Environmental Health Criteria 137, Electromagnetic Fields (300 Hz to 300 GHz), was published in 1993 as a comprehensive international review of electromagnetic-field science and health protection. The 290-page monograph was jointly sponsored by the United Nations Environment Programme, the International Radiation Protection Association, and the World Health Organization.

EHC 137 is historically important but scientifically dated. It records the evidence, dosimetry, measurement practices, exposure information, health evaluation, and protective recommendations available before the modern ICNIRP 2020, ARPANSA RPS S-1, and IEEE C95.1-2019 frameworks. It should not be used as the source of current numerical RF exposure limits.

Purpose and Coverage

The monograph covers electric, magnetic, and electromagnetic fields from 300 Hz to 300 GHz. It reviews physical characteristics, sources and exposures, measurement and dosimetry, biological interaction mechanisms, laboratory studies, human evidence, health implications, protective measures, and research needs.

Its frequency range includes intermediate-frequency and radio-frequency fields as those terms are now commonly used. The document treats electric and magnetic fields separately where near-field conditions or lower frequencies make a plane-wave relationship inappropriate, and it discusses absorption and induced quantities relevant to biological interaction.

Historical Scientific Context

EHC 137 consolidated an early international understanding that sufficiently intense electromagnetic fields can produce established effects through mechanisms that depend on frequency. At lower frequencies, induced currents and stimulation were important; across the RF range, energy absorption and heating were central concerns.

The review also considered research on reported effects at lower exposure levels. Its evaluation reflected the methods and evidence then available. Subsequent decades brought new epidemiology, experimental evidence, computational dosimetry, mobile and wireless technologies, millimeter-wave applications, systematic-review methods, and revised exposure frameworks.

Relationship to Current RF Safety Documents

Current compliance assessments should use the exposure standard, regulation, and assessment methods applicable to the jurisdiction and source. EHC 137 does not replace current ICNIRP, IEEE, national, or source-specific requirements, and numerical values quoted from it should not be presented as contemporary limits merely because the monograph remains available from WHO.

WHO's International EMF Project continues to assess health and environmental effects of electromagnetic fields and incorporates formal risk assessments into the Environmental Health Criteria series. WHO has stated that a newer radio-frequency health-risk monograph is being prepared to update the 1993 review.

Continuing Value

EHC 137 remains useful for understanding the historical development of international RF health-risk assessment. It shows how source characterization, exposure assessment, dosimetry, biological evidence, health evaluation, and protection were brought together before the present generation of standards.

For the RF Radiation Safety Reference Library, the monograph should therefore be read as a foundational scientific record rather than a compliance manual. Its value lies in tracing the development of concepts and evidence; any present-day assessment must establish the current applicable limits and methods independently.