What is Radiofrequency (RF) Radiation?

There are two types of radiation – ionizing radiation and non-ionizing radiation. Both are forms of electromagnetic energy, but ionizing radiation has more energy than non-ionizing radiation. 

  • Ionizing radiation, like x-rays or gamma rays, has enough energy to cause chemical changes by breaking chemical bonds. Sources of this type of radiation can be found in hospitals, nuclear energy plants, and nuclear weapons facilities. 
  • Non-ionizing radiation causes molecules to vibrate, which generates heat.

Common Uses for RF Radiation Include:

  • Microwave ovens
  • Radar
  • Industrial heating and sealing processes
  • Medical applications
  • Telecommunications & broadcast services. This latter category includes cellular antennas and base stations, radio and television broadcasting, radio communications for police and fire departments, microwave point-to-point radio links, and satellite communications.

At Risk Workers

The proliferation of cellular antennas and other RF-generating devices in areas where construction and maintenance work is regularly performed creates the potential for construction and maintenance workers to be exposed to harmful levels of RF radiation. At risk workers include: At risk workers

  • Roofers
  • HVAC technicians
  • Electricians
  • Masons
  • Painters
  • Carpenters
  • Laborers
  • Maintenance staff
  • Those who work in or around mobile news trucks or transmitting cameras
  • Anyone who works on rooftops, sides of buildings, and other locations where RF generating antennas are located

Health Effects of RF Radiation

The short-term thermal effects of RF radiation on humans are well documented, but less is known about the long-term health effects.  Potential thermal and non-thermal effects, including: 

  • Thermal effects: 
    • Blindness 
    • Sterility 
    • Heating of tissues – eyes and testes are particularly vulnerable 
    • Burns 
    • Electrical shocks 
  • Non-thermal effects including: 
    • alteration of body’s circadian rhythms
    • immune system
    • nature of the electrical and chemical signals communicated through the cell membrane 
  • Possibly carcinogenic to humans 
  • Potential for other disorders 
  • Interference with medical devices such as pacemakers

Symptoms of Overexposure

While there is uncertainty about the long-term health effects of exposure to RF, there is consensus around the thermal effects. Thermal effects occur when the body cannot deal with the heat buildup caused by the RF radiation quickly enough. This buildup is dependent on the frequency and intensity of the RF radiation fields as well as the length of time the worker is exposed and how close he or she is working from the source. 

Symptoms of overexposures include, but are not limited to: 

  • Labored breathing
  • Perspiring – immediate sensation of intense heating of the parts of the body exposed
  • Pain
  • Headache
  • Numbness
  • Paresthesia – a tingling or numbness, skin crawling, or itching
  • Malaise or an overall sense of feeling mentally or physically unwell
  • Diarrhea
  • Skin erythema – a reddening of the skin due to inflammation

In addition to these symptoms, workers who come in direct contact with an antenna may suffer severe burns since active RF antennas are energized (or hot). The resulting burns can be deep and may be worse than they appear. Any construction worker experiencing these symptoms should move to a new location immediately, and if the symptoms persist, see a doctor.

Hazard Identification for RF Radiation

Regulations, guidelines, and programs are intended to prevent workers and the public from exposure to hazardous levels of RF radiation, but they are only protective if employers and their employees are able to identify whether or not a hazard is present. The two main challenges facing construction employers are: 

  • Identifying the presence of RF generating devices in the areas where work needs to be performed 
  • Once identified, determine if the FCC’s exposure limits are being exceeded and what steps to take to protect their employees.

 To determine if RF generating devices are present: 

  • Look for signs and/or barriers 
  • Ask the building owner or site manager if antennas are present and their locations and request the RF radiation surveys required by the FCC. 
  • If signs and RF Radiation surveys are not available, conduct your own pre-task safety assessment. If you are unsure about your potential exposure, use a personal monitor and wear protective clothing. 

The blue “Notice” signs state that the fields beyond that point may exceed the FCC’s general public maximum permissible exposure limit. 
The yellow “Caution” sign states that the area beyond that point may exceed the FCC’s occupational maximum permissible exposure limit. 
The “Warning” sign indicates that any point beyond the sign exceeds the FCC’s human exposure limits – 10x the occupational exposure limit. 

Notice Caution Warning

If work needs to be performed within a potentially hazardous area: 

  • Check the site survey or plot plan for potential exposure levels 
  • Pre-plan work tasks and travel routes so you can limit trips through the RF field and time spent on tasks there – the goal is to get in and out as quickly as possible 
  • Contact the building manager and the antenna licensee to have the equipment powered down or moved. Do not begin work until you receive verification that the antenna has been powered down or moved. 

If the device owner and building owner are unresponsive: 

  • Contact the FCC to file a complaint – 1-888-225-5322 (press 5) 
  • Use personal monitors while work is being performed and if an alarm sounds, stop work and leave the area immediately 
  • If work must be performed in a potentially hazardous area, use personal monitors and protective clothing. 

Protective Measures for RF Radiation

Once RF generating devices have been identified, the next challenge is how to create a safe working environment for the construction workers. When deciding on the best protective measures to take consider: 

  • The distance from antennas, 
  • Whether or not the antennas are emitting RF radiation in one direction or multiple directions, 
  • The angle of the antenna. It is important to be aware that the angle of some antennas can be remotely adjusted, meaning the job may not be in the path of the antenna when work starts– but a change in the antenna’s angle could put workers in harm’s way while working, and 
  • The height of the antennas from the work surface.

Power-Down or Move the Antenna

  • If workers cannot maintain a safe distance because of the location of the work, the employer should contact the antenna owner or contact person on the warning sign.

Use a Personal RF (Field) Monitor

  • Another safeguard is to use a personal RF monitor to identify the presence of RF radiation when conducting an initial assessment and while work is underway. These devices can alert workers to potential exposures over the MPE limits by sounding an alarm, flashing lights, or vibrating when the exposure level is exceeded.

Use Protective Clothing

Protective clothing