SETTING STANDARDS IN THE PRESENCE OF DEVELOPING
SCIENTIFIC UNDERSTANDING
Frank Barnes
University of Colorado at Boulder
ABSTRACT.
The setting of standards for potential hazards as result of the application of a new technology depends on
both the philosophy with respect to risk and the state of knowledge about the circumstances under which the
technology can cause damage. Typically biological damage is first observed for high levels of exposure and
short times. As our understanding of the technology and its effects on the biology improve, biological
effects are observed at lower levels and longer exposure times. For extended low level exposures it also
becomes more difficult to demonstrate a hazard that is independent of others influences. This has been true
for electric and magnetic fields both at low and radio frequencies. In this paper it is recognized that a set
number is needed for both manufactures and system operators to meet if the technology is to serve the
public. It is also recommended that the public be presented with tables of relative risks that include levels of
exposure and other risks for comparison. Three tables of relative risks are included as a possible starting
point.
INTRODUCTION.
Standards setting bodies for safety are faced with conflicting pressures. One is to protect worker and the
public against risks for injury and health problems. Another is to make useful technology available to the
public. How these possibly conflicting requirements are met is dependent on many things including how
well the hazards are understood by the public, the regulators, the value of the technology, and the public
view of the kind of potential damage the technology may do to their health and their degree of control over
exposure to it.
The philosophy with respect to risk is important. In some circles the only safe exposure to electric and
magnetic fields is one that can be proven to have no possible health effects. Since we do not know how to
prove that all those experiments that we have not yet done will not show biological effects this is not
possible. If we were to satisfy this criteria we would not allow the generation of electricity or man made
electromagnetic radiation. The other extreme would be to have no regulations at all and shift the
responsibility for safety to the public. In practice neither of these extremes work or are followed. Standards
setting committees tend to protect against risks that occur over relatively short time scales and where the
hazards may be hard for the public recognize. For example standards exist for insulation to reduce leakage
currents below the levels where people feel a shock. However, it is still possible to hit a high voltage
distribution line with an aluminum ladder or to create a short in house wiring or an appliance that causes a
shock or starts a fire. Additionally long term low level exposures to current that might modify the growth of
cells are not taken into account in most thinking about the effects of electric fields in standard setting
discussions. In a sense these standards are not being written to protect against low probability events when
there are clear advantages to making the technology available including using it to save lives.
AN EXAMPLE AT RADIO FREQUENCIES
The approach of setting standards for high levels and short time exposures is complicated by the fact that
our scientific understanding improves over time as we get a better understanding of its effects on human
biology. For radio frequency fields the first biological effects to be observe where associated with heating.
This is clearly useful in a microwave oven or for removing a tumor or other therapy. However heating is not
desirable for cell phones if they increase you brain temperature to dangerous levels and the standards have
been set to avoid this. Other effects such as changes in free radical life times, the release of heat shock
proteins, and changes in interleukin concentrations have been observed during the last 20 years for lower
levels of exposure and for relatively long exposures. However the present standards do not take these effects
into consideration for at least two reasons. First there is not a reproducible trail of data that connects these
changes to serious health effects. Second there has not been sufficiently convincing reproducible
epidemiological data to over rides the value of the use of radio frequencies for communications in the minds
of the regulators and standards committees.
Most of the current epidemiological studies for exposures to radio frequencies (RF) fields and the incidence
of cancers have either poor exposure data or the studies have been conducted for periods of exposure that
are short compared to the predicted latency for the cancer of interest.( (Collatz et al,2005, 1999, Inskip et al
2001, Johansen et al 2001,) ) However, there are some studies that indicate that there is a correlation
between cell phone use and the incidence of brain tumors. (Hardell et al 2002, Mashevich et al. 2003, Kundi
et al 2004) If there is a cause and effect relationship between exposures to radio frequencies from cell
phones, base stations, TV and radio stations these relationships should become clearer over time as more
studies are carried out. The results of those studies that show a correlation between RF exposures, cancers
and other health effects are likely to show some kind of intensity vs. time curve. Additionally it is likely
that there will be a threshold bellow which no effects are observed. Other factors such as background stress,
diet, age, environmental factors and personal histories are also likely to be factors as to when a given level
and length of exposure leads an adverse health effect. The fact that the body has repair mechanisms and that
allergies can develop with repeated exposures will make defining the conditions when a given exposure is
harmful or helpful much more difficult than those that are developed for high level short term exposure.
From the scientific point of view this means we are going to need a much better understanding of how
electric and magnetic fields affect the human biological system.
A STRATEGY FOR NOW.
In the mean time standards groups and other political bodies need to decide what to do. Manufactures,
system operators and installers need to know what they can and cannot do. Additionally because of
economies of scale these numbers and the rules should be relatively uniform. In the case of RF base stations
they need to be installed so that they can carry the traffic and cover the desired regions. This means that
minimum signal strengths need to be available at both the cell phone and at the base station if the system is
to work. The current standards are set so that the probability that a person could position themselves near
enough to a base station so that the power absorbed would be large enough to cause a temperature rise of
1oC is very small and most situations it would not be measurable. For hand held phones the powers
densities are much larger but limited so that the calculated peak temperature rises are less than 2oC. [Li,Q
and Gandhi O. 2006]
Much of the current debate is over whether or not the allowed exposures should be greatly reduced is based
on limited data that there is a correlation between a verity of health problems and proximity to base stations.
Additionally there is a debate over whether effects other than the increase in temperature should be used to
limit the amount of radiated power.
Clearly needed are carefully constructed epidemiological studies that either show the reported health
problems are, or are not, related to the exposure to levels, the length of time for the exposures to the radio
frequency fields and any other environmental factors. These studies will need both good exposure data and
run for periods of time that exceed the latency for the cancers and other possible health problems being
studied. It is likely that short-term exposures are unlikely to cause health effects at the same level where
long-term repetitive exposures may very well lead to measurable biological changes and health effects in
combination with other adverse factors or for individuals with particular histories. There are some
indications that exposures to low levels of electric and magnetic fields behave like stress. Stress can be
either positive or negative. Stress extended over long terms can cause serious health problems and reduce
the body’s ability to respond to other stresses, such as recovering from a wound or infection.( Marucha, P.
T., etal.1998). The recommended epidemiological studies would include the collection of data that could
show if a combination RF exposure and other stress factors could lead to an increased probability of adverse
health effects.
Standards setting bodies need to take into account both the results showing biological changes at low levels
and the large number of studies that do not show any changes. Additionally they need to take into account
the benefits of having wireless communications that are used to save lives and enhance the standard of
living for a significant fraction of the public. Given the lack a strong consistent body of data showing that
exposures bellow the levels needed to cause temperature rises of a degree or more are a source of
reproducible health effects that can be linked to the exposure level, frequency, and length of exposure, it is
unlikely that current standard setting bodies will change the exposure standards.
Short of developing the kind of data that shows under what circumstances low levels of RF radiation can
cause health problems and those that will not, it is recommended that the problem be divided into two parts.
The first is as has been done for many years in setting numbers that manufacturers and system operators
must meet and the second is that tables of relative risks are distributed to the public. Since we do not live in
a risk free world it would seem to be appropriate that estimates of the risk for exposures to the field from
power lines, cell phones etc be distributed to the public so that they can make up their own minds as to the
levels of risk that they are willing to take. These tables of risk might well have more than one entry for
different levels and lengths of exposure. For example the level of risk might well be different for walking
under a power line with fields of 5 KV/m once in awhile and for living 10 or more hours a day in the same
fields. An advantage of distributing tables of risk is that it allows individuals to better understand what risks
that they are taking and to exercise more control over the risks they are willing to take just as we do when
we drive a car or work around the home. Secondly it helps remove the myth that we can have the
advantages of electric power and wireless communications with no risks. There will be those who cannot
control their exposure to levels they would like because these fields are so pervasive. How these cases will
be treated will depend to a large degree on both the political process and the public attitude toward the risk.
It will also depend on what science and technology is available to gain the desired benefits with at lower
risk.
The author has included three tables of relative risk that might be used as starting points for developing
tables of relative risk that could be used to go with information supplied by cell phone, manufactures,
system operators, power companies to customers that are concerned about possible health risks from electric
and magnetic fields. Additional material that might be added to these tables includes sunlight, and highenergy radiation. It would be no surprise if different people put somewhat different numbers on different
hazards. It would also be relatively easier to change the numbers as new information is learned than it is to
change specifications for the manufacture and installation of new equipment or require the removal of
equipment that is already in place.
Table 1 gives some estimates of the relative risks of getting a disease from a number of
sources. Table 2 gives related data for cancers. Table 3 gives another way of putting these
risks in perspective. Such tables will not remove the controversy but it should give the
public much better information.
Table 1. Relative Risk Factors for Disease Factors
Factor (Cancer type)
Smoking (lung cancer)
Benzene, Occupational exposure
(leukemia)
Asbestos, Occupational
exposure (lung cancer)
Prenatal X-ray exams (childhood
cancer)
Hair Dye (leukemia)
Powerlines (childhood cancer)
Saccharin (bladder cancer)
Excessive Alcohol (oral cancer)
Coffee (bladder cancer)
Relative Risk
10-40
References
Wynder and Hoffman 1982
1.5-20
Sandler and Collman 1987
2-6
Fraumeni and Blot 1982
2.4
1.8
Harvey et.al. 1985
Cantor et.al. 1988
Wertheimer and Leeper 1979,
Savitz et.al. 1988
IARC 1987
Tuyns 1982
Morrison and Cole 1982
1.5 – 3
1.5-2.6
1.4 -2.3
1.3-2.6
Source: (J. Lee, Bonneville Power
Administration)
Monson (1980) characterized the significance of relative risk levels as follows:
Relative Risk
1.0 – 1.2
1.2 – 1.5
1.5 – 3.0
3.0 – 10.0
Above 10.0
Strength of Association
None
Weak
Moderate
Strong
Infinite
It has been suggested by epidemiologists) that cause and effect associations are
only clearly established when relative risks are large (i.e., 5 or more) and when
data from epidemiological studies are consistent.
Table 2
Relative Risk of Getting Cancer
Risk
Source (Daily Exposure)
Carcinogen
0.3
Coffee (1 cup)
Hydrogen peroxide
0.4
Bread and grain products (average US diet)
Ethylene Dibromide
0.5
Food with pesticides (average US diet)
PCBs, DDE/DDT
8.0
Swimming in a pool (1 hour for a child)
Chloroform
9.0
Cooked bacon (100 grams)
Dimethylnitrosamine
30
Comfrey herbal tea (1 cup)
Symphytine
30
Peanut butter sandwich
Aflatoxin
60
Diet cola (12 oz.)
Sacchrin
70
Brown mustard (5 grams)
Allyl isothiosamine
90
Shrimp (100 grams)
Formaldehyde
100
Mushrooms (1 raw)
Hydrazines
300
Pain relief pill (300 mg)
Phenacetin
400
Bread (2 slices)
Formaldehyde
604
Breathing air at home (14 hours)
Formaldehyde
2,700
Regular cola (12 oz.)
Formaldehyde
2,800
Beer (12 oz.)
Ethyl alcohol
4,700
Wine (1 glass)
Ethyl alcohol
5,800
Breathing air at work (8 hours)
Formaldehyde
16,000 Sleeping pill (60 mg.)
Phenobarbital
Source:B.N. Ames, R. Magaw, L.S. Gold, 1987, “Ranking Possible Carcinogenic Hazards”; Science,V236, p 271-236.
Table 3
hazards.
Estimates of the number of days life is shortened as a result of a veriety of
Cause
Days
Cause
Days
Being unmarried-male
3,500
Drowning
41
Cigarette smoking-male
2,250
Job with radiation exposure
40
Heart disease
2,100
Falls
39
Being unmarried-female
1,600
Accidents to pedestrians
37
Being 30% overweight
1,300
Safest job accidents
30
Being a coal miner
1,100
Fire-burns
27
Cancer
980
Generation of electricity
24
Being 20% overweight
900
Illicit drug use (US average)
18
< 8 grade education
850
Poison (solid, liquid)
17
Cigarette smoking female
800
Suffocation
13
Low Socio-economic status
700
Fire arms accidents
11
Stroke
520
Natural radiation
8
Living in unfavorable state
500
Medical x-rays
6
Army in Viet Nam
400
Poisonous gases
7
Cigar smoking
330
Coffee
6
Dangerous job accidents
300
Oral contraceptives
5
Pipe smoking
220
Bicycle accidents
5
Increasing food intake 100 calories/day
210
All catastrophes combined
3.5
Motor vehicle accident
207
Diet drinks
2
Pneumonia, influenza
141
Reactor accidents-UCS
2
Alcohol (US average)
130
Reactor accidents-RCS
0.002
Accidents in home
95
Radiation from nuclear industry
0.02
Suicide
95
PAP exams
-4
Diabetes
95
Smoke detector in home
-10
Being murdered (homicide)
90
Air bags in car
-50
Legal drug misuse
90
Mobile coronary care unit
-125
Average job accident
74
Safety improvement ‘66-’76
-110
th
Source: Cohen, Bernard L. And Lee. I-sing, "A Catalog of Risks." Health Physics (36) 707-722. 1979.
Quoted in Ohio University Dept. of Environmental Health, Athens, Oh. 45701. Phone: 593-1666
Newsletter Published by Environmental Health Staff
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