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2. Health Hazards

Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.

The nature and the degree of the health effects of overexposure to RF/MW fields depend on the frequency and intensity of the fields, the duration of exposure, the part of the body exposed, the distance from the source, any shielding that may be used and other factors.

The main effect of exposure to RF/MW fields is heating of body tissues as energy from the fields is absorbed by the body. Prolonged exposure to strong RF/MW fields may increase the body temperature, producing symptoms similar to those of physical activity. In extreme cases, or when exposed to other sources of heat at the same time, the body's cooling system may be unable to cope with the heat load, leading to heat exhaustion and heat stroke.

Localized heating, or "hot spots," may lead to heat damage and burns to skin and/or internal tissues. Hot spots can be caused by non-uniform fields, by reflection and refraction of RF/MW fields inside the body or by the interaction of the fields with metallic implants, for example, cardiac pacemakers or aneurism clips. There is a higher risk of heat damage with organs which have poor temperature control, such as the lens of the eye and the testes.

For frequencies from 3 MHz to 10 MHz, worker over-exposure to time-varying electric and/or magnetic fields may result in short-term nerve stimulation.

Other hazards include contact shocks and RF burns. These effects can result from a person coming into contact with a conductor while it is exposed to RF fields. These effects should not be confused with shocks from static electricity. Electrical currents can also be induced in a person’s body, which may flow directly to the ground.

Workers with active electronic implantable medical devices (for example, pacemakers, and insulin pumps) which may be susceptible to RF/MW fields should not enter controlled spaces without first consulting their doctor.

Some laboratory studies have reported biological effects from RF/MW radiation at field levels which are too low to cause tissue heating. To date, these effects are not known to result in health hazards in workers. Although everyone is constantly exposed to weak RF fields, no health risks have been identified from this low-level exposure.

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Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.

It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.

While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.