Electromagnetic fields or EMFs, are a type of energy that occurs naturally and is also created through the use of electrical appliances and equipment. Radiowaves, microwaves, visible light, ultra-violet light and X-rays are all forms of electromagnetic energy. EMFs are made up of two components: the electric and the magnetic field.

The term EMFs is often used to refer to extremely low-frequency (ELF) electromagnetic fields. These are the ones created during use and transmission of electricity. They are also called power-frequency fields.

Typical exposures of EMFs in Canadian homes, working environments and in the community are very low. Levels of EMFs in the environment are most often measured in milligauss (mG) which is the strength of the magnetic field. Background levels of magnetic fields in urban areas are 1 mG or less.

You are exposed to EMFs when electricity runs through power lines, household wiring, lighting and electrical appliances that are plugged into the wall. Electrical equipment can create very intense fields very close to the equipment. Transmission lines create a more dispersed field. The closer you are to an electric wire or electrical equipment, including a transformer, the higher your exposure will be.

The overall risk from exposures to EMFs for people living and working in Toronto is very small. The evidence available does not suggest that exposure to EMFs at levels normally found in Canadian living and working environments is harmful.

Studies have looked at many different possible effects of EMFs. The information available shows that EMFs probably do not cause heart disease or breast cancer.

In 2002, the International Agency for Research on Cancer (IARC) classified the magnetic component of EMF as a possible carcinogen. This classification was based on studies that showed an association between higher levels of magnetic fields in the home and the rate of childhood leukemia. However, the data available are still insufficient to draw a firm conclusion on the cancer causing effects of EMFs. Areas of uncertainty include: understanding how EMFs could cause cancer; the type of exposure that might be important (short periods of exposure to high levels or long periods of exposure to low levels); and not enough evidence in experiments with animals.

There are simple ways to reduce your exposure. Electric and magnetic fields decrease rapidly as you move away from the source. This means that increasing the distance between you and a source of EMFs (power lines or electrical appliances) will easily reduce your level of exposure to EMFs.

In your home:

You can arrange furniture and activity areas so that you do not spend a lot of time where EMFs are highest. Places where EMFs are usually the highest include:

• The electrical distribution lines
• The main circuit box
• Major energy consuming appliances (such as fridge, stoves, TV, computers)

Reducing electricity use and unplugging non-essential electrical appliances when they are not in use you may also reduce the levels of EMFs in your environment.

At the office:

• Where possible, keep major equipment such as photocopiers and printers away from your immediate work area.
• Keep at least 50 cm from you computer monitor. Older monitors, especially CRT monitors, typically emit higher levels of EMFs than newer flat screen monitors.

In the community:

• Spend less time close to large sources of EMFs such as under high-voltage transmission lines (hydro corridors) and transformers.

The City of Toronto has adopted a prudent avoidance policy for exposures to EMFs in and next to hydro corridors. This means that potential exposures to EMFs are taken into account when new parks, sports fields, trails and recreational equipment are planned in hydro corridors. Toronto Public Health will review an EMF Management Plan before construction starts.

The City of Toronto also encourage developers of properties that are next to hydro corridors to reduce potential exposures in buildings such as residences, schools and childcare centres where children would be expected to spend a long time. Developers are also asked to submit an EMF Management Plan to show how they have reduced exposures.

An EMF management plan is a document that outlines what can be done to reduce exposures to EMFs. For example, a plan for a new park in a hydro corridor can identify the best location for play equipment or other amenities where children are likely to spend time.

Toronto Public Health has a guide "EMF Management Plan Guidance Document" to help people who are planning new buildings or infrastructure in or next to hydro corridors prepare an EMF management plan.

Read Toronto Public Health's reports on electromagnetic fields and hydro corridors.

• Reducing Electromagnetic Field Exposure from Hydro Corridors (Staff report to the Board of Health)
• An Assessment of Health Implications Associated with Exposures to Electromagnetic Fields in and next to Hydro Corridors in the City of Toronto

Other sources of information you might find useful include:

Links to sites external to the Toronto Public Health Web site are provided as a convenience and their inclusion does not imply that Toronto Public Health endorses or accepts any responsibility for the content or use of these sites.

• Health Canada: Electric and Magnetic Fields at Extremely Low Frequencies
• Canadian Cancer Society: Electromagnetic fields
• World Health Organization: Electromagnetic Fields