Electromagnetic, that is to say electrical and magnetic fields (EMF) both natural and electrically produced, exist throughout our environment and we are all exposed to them constantly. Electric fields are produced by electric charges and measured in volts per metre (V/m) whilst magnetic fields are produced by the motion of electric charges and measured in amperes per metre (A/m).
Whether or not these fields are harmful has been a matter of some debate for many years and remains largely unresolved.
What Is It?
Magnetic fields arise only when an electric current is flowing, so that when welding power sources and other equipment are being used there are associated magnetic fields being produced. Magnetic waves have frequency and wavelength and travel at the speed of light.
Sources
Anything that is powered by electricity, when it is operating and current is flowing is a source of a magnetic field.
Composition
The strength of a magnetic field is measured in A/m, but it is normally expressed in 'Tesla, (T)' or 'Gauss, (G)' and these are units of magnetic induction.
Effects
The effects of low frequency magnetic fields have been studied and the evidence of these studies suggests that they do not affect the functioning of the human body and there is as yet no evidence of any serious adverse health effect.
Limits
Exposure limits set to provide protection from known health effects of all EMF are contained in a guideline document produced by the International Commission on Non-Ionizing Radiation Protection.
Control and Prevention
Electromagnetic fields pass through most common materials and so control of exposure by screening or shielding is not possible. Therefore the only practicable means of control in the workplace is to increase the distance between the source of the magnetic field and the worker, since magnetic fields decrease rapidly as the distance from the source increases.
First Aid
In the event of someone wearing a heart pacemaker or other electromedical device experiencing difficulties, e.g. fainting, the casualty should be removed from the source of magnetic field or the source switched off.