Static Fields

8. Should the public and workers be protected from the effects of static fields?

The source document for this Digest states:

National authorities are recommended to implement programs that protect both the public and workers from any untoward effects of static fields. However, given that the main effect of Static electric fields is discomfort from electric discharge to tissues of the body, the protective program could merely be to provide information on situations that could lead to exposure to large electric fields and how to avoid them. A program is needed to protect against established acute effects of static magnetic fields. Because sufficient information on possible long-term or delayed effects of exposure is currently unavailable, cost-effective precautionary measures such as those being developed by WHO (www.who.int/emf ) may be needed to limit the exposures of workers and the public.

National authorities should adopt standards based on sound science that limit the exposure of people to static magnetic fields. Implementation of health-based standards provides the primary protective measure for workers and the public. International standards exist for static magnetic fields (ICNIRP, 1994) and are described in Appendix 1. However, WHO recommends that these be reviewed in light of more recent evidence from the scientific literature.

National authorities should establish or complement existing programs that protect against possible effects of exposure to static magnetic fields. Protective measures for the industrial and scientific use of magnetic fields can be categorized as engineering design controls, the use of separation distance, and administrative controls. Protective measures against ancillary hazards from magnetic interference with emergency or medical electronic equipment, and for surgical and dental implants, are a special area of concern regarding possible adverse health effects of static magnetic fields. Precautions must be taken because of the mechanical forces imparted to ferromagnetic implants and loose objects in high-field facilities.

National authorities should consider licensing MRI units in order to ensure that protective measures are implemented. This would also allow additional requirements for MRI units with strengths in excess of local national standards or 2 T to be complied with. Such requirements relate to provision of information on patients, workers and any incidents or injuries resulting from the strong magnetic fields.

National authorities should fund research to fill the large gaps in knowledge that pertain to the safety of people exposed to static magnetic fields. Recommendations for further research form part of this document (see below) and are posted on the WHO web site: www.who.int/emf . Researchers should be funded to conduct studies recommended in this WHO research agenda.

National authorities should fund MRI units to collect information on worker exposure to static magnetic fields and patient exposure to MRI. These should be available for future epidemiological studies. They should also fund databases collecting information on exposures to workers where high long-term exposures occur, such as those involved in the manufacture of MRI or similarly high strength magnets and new technologies such as MagLev trains.

Source & ©: WHO "Environmental Health Criteria 232: Static Fields" (2006)
 Chapter 1, Section 1.1.8 Recommendations for national authorities

For more information on	See EHC 232
Recommendations for national authorities	Chapter 10