OHS Canada Magazine


January 11, 2011
By Emily Landau
Health & Safety

These days, employers and workers alike are becoming more aware that environmental hazards on the outside can infiltrate workplaces on the inside. Lately, though, the buzz has been growing around a potential enemy launching a sneak attack through wires and plugged-in devices.

“Dirty electricity” is a simpler term for high-frequency voltage transients, which are electromagnetic fields (EMF) produced whenever power signals are transformed. “Dirty electricity is caused by sparking, arcing and anything that interrupts current flow,” explains Dr. Samuel Milham, an epidemiologist in Indio, California.

Kevin Byrne, an engineer and the president of EMF Solutions in Toronto, says that any electronic devices commonly found in workplaces – including computers, monitors, printers, phones and compact fluorescent light bulbs – are capable of producing dirty electricity.

Some experts suggest that these filthy fields pose health risks; others insist claims of adverse bio-effects are unfounded. So, what’s the dirt?

Before the advent of modern electronics, electrical current was smooth and continuous, vibrating at a base frequency of 60 hertz (Hz), says Lawrence Gust, an engineer and environmental consultant in Ventura, California. But newer electronics rely on voltage converters, which transform the standard 120 volts (alternating current) into lower voltage (direct current) to allow plugged-in devices to run, Gust says.


“The process for doing that creates different frequencies that are much higher than the base frequency of the electricity,” he explains, adding that these frequencies can reach levels ranging from two to 100 kilohertz (kHz).

The rub, Byrne suggests, is that not all energy is trapped in the wire, and this is where concerns begin to manifest. Some of the energy emitting from the wire creates an electric field, he says, and “dirty electricity rides on the electric field.”

As to how far beyond the wire dirty electricity radiates, Gust can offer no specific measure, but posits that its effect depends on the sensitivity of the user. If a person is two metres away, “probably no problem,” he says. If just one metre away, however, “maybe there’s some sensitivity there.”

In an office environment, Gust says, “everyone is close enough to one of these things” to be within two metres.

While devices such as computers and printers carry dirty electricity, Byrne says the levels associated with laptop computers might be particularly high. “Electrical fields are looking for capacitance” – the ability of a system to store an electrical charge, he explains. “The laptop is basically a battery being charged right under your hands,” creating an electric field that “will want to go through you to ground.”

Dirty electricity is measured in GS units, the units read by the Graham-Stetzer microsurge meter. “You want it to be below 50 GS for a safe level,” Byrne advises.

To reduce dirty electricity in wiring, he recommends installing a GS filter. Gust suggests the filter “gives the electrical line a haircut. It chops off all these [voltage] spikes. Therefore, it prevents these things from getting back on the wiring.”

But filter effectiveness is not without debate. A 2006 report from Health Canada, focusing on residential settings, states that the “filter does not clean up line voltage harmonics.”

In fact, the report notes, the filter’s “distortion products (harmonics) are carried on the electricity supply and add to the level of ‘dirty electricity’ in the house.”


If dirty electricity is regularly surging through offices, the million-dollar question is bound to arise: is it having a negative impact on worker health?

In the opinion of some researchers, the answer is yes. “In animal work and other work, they’ve noticed that if you pulse or if your [EMF] wave forms rise and fall steeply, you get more bio-effects,” Dr. Milham says.

Bodies are bio-electric, Byrne notes, suggesting that “when you interfere with your body’s natural processes, you start to get symptoms and development of diseases.”

And when “you stick exogenous currents into this delicate electrical soup that evolved over years,” adds Dr. Milham, “it screws things up.”

Some research has even linked dirty electricity to long-term health conditions, such as diabetes and cancer. In 2009, Magda Havas, Ph.D., an associate professor of environmental and resource studies at Peterborough, Ontario’s Trent University, conducted a study that found “the increasing exposure and ubiquitous nature of electromagnetic pollution may be contributing to the increasing incidence of [diabetes].”

Specifically, Havas’s findings suggest the plasma glucose levels of patients with diabetes “respond to electromagnetic pollution in the form of radio frequencies in the kHz range associated with indoor wiring.”

Dr. Milham’s own retrospective study of teachers at a school in California, published in 2008, correlates exposure to high-frequency voltage transients with an increased incidence of cancer. Sixteen teachers in a cohort of 137 hired between 1988 and 2005 were diagnosed with 18 cancers.

The study notes that 60-Hz magnetic fields showed no association with cancer incidence. However, teachers who had worked at the school for more than 10 years and “had ever worked in a room with an overload GS reading had a much higher rate of cancer,” Dr. Milham found.

“The cancer incidence in the teachers at this school is unusually high and is strongly associated with high-frequency voltage transients, which may be a universal carcinogen, similar to ionizing radiation,” the study contends.

Other less severe symptoms have also been reported by workers, including some who claim specific vulnerability to EMF, called electrical hypersensitivity (EHS).

The Geneva-based World Health Organization (WHO) states this hypersensitivity is “characterized by a variety of non-specific symptoms,” the collection not being part of any recognized syndrome. It lists potential symptoms as dermatological (redness, tingling or burning) and neurasthenic and vegetative (fatigue or tiredness, difficulty concentrating, dizziness, nausea, heart palpitations and digestion problems).

While EHS may not be linked to any specific condition, the WHO notes that its reported symptoms are “certainly real and can vary widely in their severity.”

Indeed, many members of the Ontario Secondary School Teachers’ Federation (OSSTF), based in Toronto, have complained of EHS, reports Jane Ste. Marie, the federation’s executive assistant of health and safety. “We’re having a very difficult time trying to accommodate them in the workplace,” Ste. Marie says of affected employees.

Because of a dearth of concrete information on the health impacts of dirty electricity, she says the OSSTF must address concerns on a case-by-case basis.

While GS filters are recommended, Byrne suggests the best way to minimize exposure is to reduce contact with and proximity to devices of concern. “Distance is your friend,” Gust says, although office layouts make this tough to achieve.


Like many emerging concerns, dirty electricity has generated widespread debate among researchers, medical personnel and those who report experiencing EHS. Dr. Milham acknowledges that this is all “new stuff,” but adds he has no doubt that dirty electricity can negatively impact health.

Not so for Linda Erdreich, Ph.D., an epidemiologist and senior managing scientist at Exponent, an engineering and scientific consulting firm in New York City.

“I have concerns about the validity of the question that there’s dirty electricity that adversely affects your health,” Dr. Erdreich states. “I find the studies have flaws in the methodology of doing studies with people and in the exposure assessments,” she adds.

Tara Hargreaves, a staff scientist at the Radiation Safety Institute of Canada in Toronto, is also skeptical. “Right now, the only effect that these types of fields can seem to have on the body is heating effects,” Hargreaves says.

In terms of EHS, she agrees that “there are certainly people who do have symptoms.” However, adds Hargreaves, “whether those symptoms can actually be attributed to the electromagnetic fields is something that is being determined.”

A fact sheet from the WHO seems to support that view. While recognizing that real symptoms exist, the information goes on to say “EHS has no clear diagnostic criteria and there is no scientific basis to link EHS symptoms to EMF exposure.”

EHS might be related to psychiatric symptoms or to the “stress reactions as a result of worrying about EMF health effects, rather than the EMF exposure itself,” the fact sheet notes.

Gust dismisses these suggestions, contending that the lack of any conclusive evidence is the result of “limited resources,” rather than the absence of a link.

Until the time when more conclusive results have been unearthed, Byrne recommends that workers avoid close exposure to electronic devices as much as possible. Proximity “is the cause of a lot of today’s modern illness,” he insists.

Follow us on Twitter @OHSCanada

Emily Landau is editorial assistant of OHS CANADA.



Wired electronics are not the only cause for health concerns, some experts say. Wireless devices like cellphones, portable telephones and WiFi routers can also produce significant electromagnetic fields (EMF).

Consider cellphones, notes Alasdair Philips, an engineer and director of Powerwatch, based in the United Kingdom. “Cellphones emit quite high levels of both low-frequency magnetic fields from the battery current pulses, that go right through the user’s head and, of course, significant levels of microwave signals,” Philips reports. “All offices should have fully wired phones for a healthy work force,” he contends.

The farther from the source, the better, agrees Dr. Samuel Milham, an epidemiologist in Indio, California. “Putting a cellphone or a portable phone against your head is like sticking your head in a microwave oven,” Dr. Milham offers.

Unlike wired devices, which produce electricity only when in use, wireless communications emit “radiation full-time, 24/7, from the base, even when you’re not using them,” says Kevin Byrne, president of EMF Solutions in Toronto.

Wireless devices create both magnetic fields and radiofrequency (RF) fields, Byrne says. Keeping wireless routers in separate rooms from workers should be a priority, he advises, since RF exposure can be mitigated by walls.

Philips says that wireless exposure produces similar symptoms to those experienced by people suffering electrical hypersensitivity. “Symptoms of wireless exposure include concentration difficulties, headaches, high levels of fatigue and tiredness – the last things you want in a workplace,” he notes.

However, the World Health Organization in Geneva reports that although exposure to RF fields in cellphones has been scientifically connected to “changes in brain activity, reaction times and sleep patterns,” these changes are minor. “No recent national or international reviews have concluded that exposure to the RF fields from mobile phones or their base stations cause any adverse health consequence,” the organization adds.


Stories continue below

Print this page

Related Stories