Swiss health officials are recommending that people stay at least 30 centimetres away from energy-saving light bulbs, over electrosmog concerns.
A study has measured the electric fields emitted from these lamps and concluded that a certain distance is needed to keep well under international limits.
Low- and medium-frequency magnetic and electric fields can induce electric currents in the body which, above a certain frequency, can stimulate the nerves and muscles.
The Swiss study, undertaken for the federal offices of health and energy, found that medium-frequency electric fields were primarily responsible for these currents. Depending on the lamp, current field densities in the immediate vicinity reach 10-55 per cent of the exposure limit.
As this weakens with distance, health officials have recommended as a personal precaution to maintain a gap of at least 30 centimetres, for example from a desk lamp that is being used for a long time.
Switzerland started to phase out the least efficient categories of light bulbs at the beginning of last year and will officially follow the European Union's line on 100W lamps from September 1, 2010.
From 2012, only bulbs meeting or exceeding mid-category D requirements will be on sale - the equivalent to banning conventional light bulbs.
swissinfo.ch and agencies