This new ANSES expert appraisal sought to analyse all the new scientific knowledge available on exposure to low-frequency electromagnetic fields and the possible biological and health effects. To better characterise levels of population exposure, particularly in the home, ANSES also financed a number of measurement campaigns.
Improved knowledge of exposure
Populations are exposed to many sources of electromagnetic fields, including power lines, transport and transformers outside the home, or household appliances inside the home. The many studies conducted since 2010 have given us a clearer picture of population exposure to low-frequency electromagnetic fields.
In particular, they show that the highest values outside the home are measured primarily under very-high-voltage power lines or next to transformers and electricity substations. Inside the home, household appliances may produce high levels of magnetic field, but exposure in this case is brief and highly localised.
Limit the exposure of vulnerable populations close to high-voltage power lines
In 2010, ANSES underlined a convergence in epidemiological studies showing an association between the occurrence of childhood leukaemia and exposure to low-frequency magnetic fields at levels exceeding 0.2 µT or 0.4 µT. In the light of new data, the Agency is confirming the “limited” level of evidence associated with this long-term effect, even though this association is found less frequently in studies published after 2010.
As part of this expert appraisal, ANSES financed a study to quantify the proportion of the French population – and more specifically the proportion of children – who are exposed to this level of field, emitted by high-voltage power lines. Conducted by a team from INSERM and Caen University Hospital, the study indicates that around 40,000 children under 15 years of age (0.35% of the population) are exposed to a magnetic field of over 0.4 µT in their homes, and that around 8,000 children (0.18%) are exposed to a magnetic field of over 0.4 µT in their schools.
In view of these results, the Agency is again recommending a precautionary approach that would limit the number of vulnerable people exposed to high-voltage power lines, as well as limiting exposure. To this end, it recommends not building or developing new facilities attended by vulnerable people (hospitals, schools, etc.) immediately next to very-high voltage power lines, or running new power lines over these facilities.
ANSES points out that existing regulations in France govern exposure levels only next to electricity transmission and distribution lines, by setting an exposure limit. The Agency therefore recommends extending this regulatory provision to all sources of electromagnetic field to which the general population is exposed.
Manage occupational exposure
Levels of worker exposure to low-frequency magnetic fields vary considerably, depending on the occupation held. A study conducted by the French National Research and Safety Institute (INRS) and the Occupational Health and Pension Insurance Funds (CARSAT) showed that some workers could be exposed to very high field levels. These could potentially exceed exposure limits (1,000 µT at 50 Hz) in specific circumstances, for example when using some types of industrial machinery.
In consequence, ANSES reiterates the importance of enforcing regulatory provisions in occupational health and limiting situations of overexposure, particularly by adapting workstations. In addition, ANSES recommends that manufacturers of industrial machines emitting low-frequency electromagnetic fields measure the exposure associated with machine use, and include these data in the technical specifications provided to customers and users.
Moreover, experimental studies have highlighted possible biological effects (oxidative stress, genotoxic stress, effects on cellular physiology) at the high levels of exposure sometimes encountered in the workplace. Nevertheless, the Agency indicates that the results of epidemiological studies are too heterogeneous to establish a link between occupational exposure and the development of chronic diseases, particularly neurodegenerative diseases and tumours of the nervous system. It appears necessary to continue research into the possible risk of diseases associated with exposure to low-frequency magnetic fields. At the same time, the Agency recommends that the next assessment of exposure limits should take into account the most recent scientific data available.
Lastly, the Agency draws attention to the specific case of pregnant women exposed in the workplace. In some scenarios of occupational exposure, it has been shown that the induced current density in the foetus may exceed the limits recommended for the general public. ANSES therefore recommends providing better information to women and raising awareness of the regulatory provisions allowing them to adapt their working conditions when they are pregnant, in order to limit foetal exposure to low-frequency electromagnetic fields.