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I made this post because I have a safety concern about my job as medical device tester. I was reading the user manual of the equipment I work with and found the next warning:

“Per FCC regulations, maintain a distance of at least 7.8 inches/20 cm between the Radio Card on the unit and a human body”

I work with 6 units, which each one has a small wireless antenna, but I also have coworkers that work with the same number of units, resulting in 36 units in total.

My question is if there is any risk for being exposed to the radiation of these equipment, by risk I mean getting cancer.

Notes: The wireless of the units are enabled, but we are not connecting the devices to computers, we are testing other functionalities.

The units operates on the following frequencies with a maximum radiated power of 100 mW:

• 802.11a: 5 GHz band, up to 54 Mbps physical RF specification.

• 802.11b: 2.4 GHz band, up to 11 Mbps physical RF specification.

• 802.11g: 2.4 GHz band, up to 54 Mbps physical RF specification.

• 802.11n: 5 GHz or 2.4 GHz band, up to 72 Mbps physical RF specification.

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closed as off-topic by Andy aka, Chupacabras, Leon Heller, Dave Tweed Jun 10 at 12:40

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Andy aka, Chupacabras, Leon Heller, Dave Tweed
If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Speak with the people whose manual you read. \$\endgroup\$ – Andy aka Jun 10 at 8:19
  • \$\begingroup\$ The short answer is no, but what country are you in? \$\endgroup\$ – nekomatic Jun 10 at 8:27
  • \$\begingroup\$ You will have to make your own guesses about this. In general, we don't know enough to draw bright lines for you. And the desire by public non-health regulatory agencies in the US to protect public health is mostly driven by corporate interests. The NIH says 7g of Tylenol in a day is sufficient to cause "serious liver damage." But for decades 4g per day was the recommended daily usage limit. And 2g was considering the minimum effective dose. You'll have to work out your own comfort level. \$\endgroup\$ – jonk Jun 10 at 8:34
  • \$\begingroup\$ I live in California, USA. I was reading that a modern cellphone radiates around 1.6 Watts/ Kg. Not sure If my conclusion is right, but all these 36 devices would be equal to 4 smartphones. \$\endgroup\$ – Kaizen90 Jun 10 at 8:42
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    \$\begingroup\$ Radiation density goes down by squared value of distance. So, you cannot simply add nominal values of transmit power of those devices. \$\endgroup\$ – Chupacabras Jun 10 at 9:16
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A lot of people worry about health effects of electromagnetic radiation, and you'll find a lot of scaremongering misinformation on the web, but it is generally agreed by doctors and scientists that the electromagnetic radiation from WiFi equipment is extremely unlikely to cause any remotely significant risk of cancers. The World Health Organization says:

Despite many studies, the evidence for any effect remains highly controversial. However, it is clear that if electromagnetic fields do have an effect on cancer, then any increase in risk will be extremely small. The results to date contain many inconsistencies, but no large increases in risk have been found for any cancer in children or adults.

A number of epidemiological studies suggest small increases in risk of childhood leukemia with exposure to low frequency magnetic fields in the home. However, scientists have not generally concluded that these results indicate a cause-effect relation between exposure to the fields and disease (as opposed to artifacts in the study or effects unrelated to field exposure). In part, this conclusion has been reached because animal and laboratory studies fail to demonstrate any reproducible effects that are consistent with the hypothesis that fields cause or promote cancer. Large-scale studies are currently underway in several countries and may help resolve these issues.

In a comment on your question you said that I was reading that a modern cellphone radiates around 1.6 Watts/ Kg. That's a measure of specific absorption rate which is not the same thing as the radiated power of your WiFi devices.

In general if you have a concern about the safety of your workplace, your first step should be to find out what the law where you are says and whether your company is complying with it. For example if you were in the UK there would need to be a risk assessment for the task you were doing, documenting what hazards had been identified and what measures needed taking to reduce them. If you aren't happy with the process or your company's compliance with it then you would need to look at what options you have for resolving that with your employer, either internally (using company procedures) or externally (using the law).

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  • \$\begingroup\$ What is the difference between the radiation generated by a cellphone and a wireless device? \$\endgroup\$ – Kaizen90 Jun 10 at 16:49
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Are you within 20cm of the radios?

Those warnings are generally in place as a defense against lawsuits, meaning if you did get sick they would say you ignored the warnings and so it isn't their fault.

That doesn't mean that being within 20cm is dangerous, it just means they think if it was dangerous that being outside 20cm might be safe(er).

How do they come up with the number? Who knows, they may have actual research on rodents or something or they might just do some math and think that sounds like a good number. Obviously they can't pick an unreasonable distance or no one could use the device within the safety guidelines.

FFC type regulations often don't mean much, unless you want to sue someone or not be sued yourself. In the past they have been horribly wrong and you have lots of cases of things with no evidence of being dangerous getting banned due to pressure from lobby groups.

There are some difficulties with this area. Firstly it's practically impossible to do a controlled study on humans, since all of us are subject to a bunch of RF radiation. Where are you going to get your control group that doesn't have a cell phone or WiFi?

Unless there is new research I'm unaware of, there has previously been no known biological interaction with RF and human tissue that could cause the sort of cell damage required to cause cancer. This is true of all non-ionizing radiation, there simply is no known method for it to cause us harm in that way.

It can certainly heat you up to the point you would burn if there was enough power, so I wouldn't recommending standing in the path of a really high power transmitter up close.

Of course not knowing of a way it can be harmful doesn't mean it's perfectly safe either. I can really only suggest you read some proper peer reviewed studies on the effects of RF and make your decisions based on that. Keep up with the latest research so you know if anyone does find some risk factors you need to think about.

There is a lot of scare mongering out there, but you can usually identify it because they want to sell you something.

Also make sure your work place is following any relevant safety guidelines.

I should also say there are studies that show a statistical link between RF exposure and cancers. They aren't great studies because they don't really eliminate other environmental factors well. One I recall was of military radar operators from several different countries where they all had statistically significant increases in rates for certain cancers compared with other personnel and the general public. The other I remember was done on people diagnosed with certain head tumors and studied their mobile phone usage, which found most of the patients had high levels of mobile usage.

So there has been some statistical evidence, even if the mechanism is unknown. But like I said, these studies don't really control for other factors. For example high powered radar equipment is constructed with a bunch of fairly toxic materials, how much exposure did the operators have to these? The study did not investigate that.

Mobile Phone Study

Radar Operator Study

Accuse me of scare mongering if you want, but it's not fair to say there hasn't been evidence of correlation. Which is not causation, obviously.

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    \$\begingroup\$ Scare monger much yourself? The studies you mention towards the end are the fringe, and have not been replicated. You are remembering what some scare mongering reporter said, and repeating it. Look up those studies. I think you'll find there is very little truth to them. \$\endgroup\$ – JRE Jun 10 at 10:35
  • \$\begingroup\$ No I've read the papers. I can find and link them if you really want. \$\endgroup\$ – hekete Jun 10 at 10:38

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