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www.mast-victims.org forum / Health / Documents of the NRPB.. Volume 4 No 5 1993
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Anonymous
# Posted: 3 Jul 2006 04:04
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Statement by the National Radiological Protection Board
Restrictions on Human Exposure to Static and Time Varying Electromagnetic Fields and Radiation
SCOPE
1. The Board has responsibility for providing advice on appropriate restrictions on the exposure of people to electromagnetic fields and radiation. These include static, power frequency (50 Hz) and other extremely low frequency (ELF) electric and magnetic fields, and radiofrequency (RF) fields and radiation. Previous guidance limiting exposure to time varying electric and magnetic fields was issued in 1989 (1).
2. These revised recommendations are based on an assessment of the possible effects on human health derived from biological information (2-4), from dosimetric data (5,6) and from studies of exposed human populations (7,8). They apply equally to workers and to members of the public but not to people who are exposed to electromagnetic fields and radiation for medical diagnostic or therapeutic purposes; guidance for the protection of patients and volunteers during clinical magnetic resonance diagnostic procedures has been issued separately (9). These recommendations are intended to provide a framework for a system of restrictions on human exposure to these fields and radiations (10).
PRINCIPLES
3. A large number of studies of human populations exposed to electromagnetic fields and radiation have been carried out. They have examined general health, birth outcome and cancer incidence. These epidemiological studies have been reviewed elsewhere (7). In addition, an Advisory Group set up by the Board has examined in detail the evidence for an association between the incidence of childhood and adult cancers and exposure to electromagnetic fields.
Editor's note: No. 4 below says there is no clear evidence of adverse health effects from EMF at levels "to which people are normally exposed". Victims of this highly-classified, clandestine experimentation do not know what level of signal strength which we are exposed to. We do know it is concentrated and persistent and it is not of 'normal' nature. Also the chance of it being of a multiple variety of radiation emissions is quite likely. Again, we know that it has the characteristics to not just send microwave signals, but to retrieve them in usable audio and video form from any selected target.
4. It can be concluded from these reviews that there is no clear evidence of adverse health effects at the levels of electromagnetic fields to which people are normally exposed. In particular, the epidemiological data do not provide a basis for restricting human exposure to electromagnetic fields and radiation (11); the revised guidance is based on available biological data describing thresholds for well-established direct and indirect effects of acute exposure.
5. Direct effects are those resulting from the interaction of electromagnetic fields or radiation with the human body, whereas indirect effects are those resulting from an interaction between electromagnetic fields or radiation, an external object such as a vehicle or other metallic structure, and the human body.
Direct effects
6. The adverse consequences of direct effects of exposure are avoided by complying with appropriate basic restrictions derived from a consideration of biological responses.
7. It is not possible to recommend basic restrictions to avoid the direct effects of human exposure to static electric fields; guidance is given for the avoidance of the annoying effects of direct perception of the surface electric charge and for indirect effects such as electric shock.
8. The restrictions on acute exposure to static magnetic fields are based on avoiding acute responses such as vertigo or nausea and adverse health effects resulting from cardiac arrhythmia and impaired mental function. In view of the relative lack of information from studies of exposed populations regarding possible long-term effects of high fields the Board considers it advisable to restrict long-term (time-averaged) exposure to levels of one-tenth of that intended to prevent acute responses.
9. The restrictions on exposure to ELF electric and magnetic fields are intended to avoid the effects of induced electric currents on functions of the central nervous system such as the control of movement and posture, memory, reasoning and visual processing. Exposure to much higher electric or magnetic fields has been reported to result in headaches and nerve and muscle stimulation.
Editor's note: No. 10 below mentions the heat and increased body temperature which exposure can produce. We (victims) have all experienced this, with the sweating and general discomfort, so we know that part of the signal spectrum is similar.
10. Heating is a major consequence of exposure to RF (including microwave) radiation. Restrictions on exposure are intended to prevent adverse responses to increased heat load and elevated body temperature. These responses include increased cardiac output associated with elevated skin blood flow and sweating. Increased body temperature may result in decreased mental function and other physiological changes. At very high power absorption, such exposures may eventually result in headaches, nausea, dizziness and, eventually, circulatory collapse and loss of thermoregulatory control, and in extreme cases can be fatal. The advised restriction of the specific energy absorption rate (SAR) averaged over the whole body incorporates a sufficient margin of safety so that it is not necessary to account for additional environmental factors and work loads.
11. For those exposures in which the distribution of absorbed power within the body is highly non-uniform, exposure may be limited primarily by restrictions placed on localised heating. Restrictions on exposure are intended to prevent adverse effects of elevated local tissue temperatures. It is considered that tissues of the trunk and limbs are less sensitive to elevated temperature than are tissues of the head. In particular, heating of the eye can eventually result in lens opacities, and localised heating of brain tissue can induce inappropriate physiological responses.
12. Heat has been shown to be teratogenic in various animal species, including primates, and has been associated with central nervous system and facial defects in children whose mothers experienced moderate to severe hyperthermia, especially during the first trimester of pregnancy. Restrictions on localised SAR within the embryo and fetus are intended to prevent such adverse developmental outcomes. It is considered, however, that compliance with the advised restrictions on whole-body and localised SAR in the mother will afford sufficient protection.
13. As frequency increases, the depth of penetration in the body decreases and the deposition of energy becomes more superficial. For frequencies greater than about 10 GHz the absorption of microwave energy becomes confined to increasingly superficial layers of the skin and to the cornea. It then becomes more appropriate to use power density as the quantity in which the basic restriction on exposure is expressed rather than SAR averaged over a broad expanse of a thin layer of skin.
Editor's note: the last line in No. 14 below - "it is recommended that exposure under conditions in which the auditory effect can be evoked in people with normal hearing should be avoided."
14. Pulsed RF (including microwave) radiation can interact with tissue to produce effects which are different from those elicited by continuous wave (CW) radiation. Some of these responses seem to be well established, such as the microwave-induced auditory response which probably results from very rapid thermoelastic expansion of the brain creating a sound wave in the head. It is recommended that exposure under conditions in which the auditory effect can be evoked in people with normal hearing should be avoided.
Indirect effects
15. An electrically grounded person touching an ungrounded metallic object in a static or ELF electric field may draw an electric current from the object and may experience a microshock (spark discharge). A person touching a metallic object situated in a sufficiently intense RF field may experience a shock or burn. The possibility of occurrence of repeated microshock, electric shock and RF burns may be determined by the measurement of contact current. Such effects may be avoided by limiting the external electric field or by other engineering or administrative controls.
16. Pacemakers or other electrically or magnetically sensitive prosthetic devices may be affected by electric and magnetic field strengths lower than those that correspond to the basic restrictions, but these effects are not considered explicitly (10). Advice on their use should be obtained from the manufacturers or those responsible for implanting such devices.
Basic restrictions
17. Restrictions on the effects of exposure to time varying electric and magnetic fields and electromagnetic radiations are based on biological considerations and are termed 'basic restrictions'. Depending on frequency, the physical quantities used to specify the basic restrictions are: current density (unit ampere (A) per square metre), specific energy absorption rate (SAR) (unit watt (W) per kilogram) and, for pulsed radiation, specific energy absorption (SA) (unit joule (J) per kilogram) and power density (unit watt (W) per square metre). These dosimetric quantities cannot be obtained directly by means of a measuring instrument, except for power density which can be related to measurement of electric and magnetic field strengths. The basic restriction for static magnetic fields is given in terms of magnetic flux density (unit tesla, T) which can be measured directly.
Investigation levels
18. Investigation levels are values of electric field strength, magnetic field strength, magnetic flux density, power density, and contact current provided for the purpose of comparison with values of measured field quantities for investigating whether compliance with basic restrictions is achieved. If the measured values are greater than the relevant investigation leve

Anonymous
# Posted: 3 Jul 2006 04:06
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Restrictions on Human Exposure to Static and Time Varying

Electromagnetic Fields and Radiation
Scientific Basis and Recommendations for the Implementation of the Board's Statement

ABSTRACT
The Board has revised its advice, previously issued as NRPB-GS11, on restrictions on human exposure to electromagnetic fields and radiation. The revised recommendations are based on an assessment of the possible effects on human health derived from biological information, from dosimetric considerations of the interaction of electromagnetic fields with people and from studies of exposed populations, and are intended to provide the rationale and conceptual framework for a system of restrictions on human exposure to these fields and radiation; it is intended to develop additional guidance for specific exposure conditions in the workplace. The recommendations are designed to prevent acute, direct effects of exposure such as vertigo and nausea caused by exposure to static magnetic fields, the effects of induced, low frequency electric current on the functions of the central nervous system, and adverse responses to increased heat load and elevated tissue temperature resulting from exposure to radiofrequency and microwave fields and radiation. In addition, guidance is given for the avoidance of the annoying effects of the direct perception of surface electric charge, and for the avoidance of indirect effects such as repeated microshocks (spark discharges), electric shock and radiofrequency burn. The recommendations apply equally to workers and to members of the public but not to people who are exposed to electromagnetic fields for medical diagnostic or therapeutic purposes.
PREPARED BY A F McKINLAY, S G ALLEN, P J DIMBYLOW, C R MUIRHEAD AND R D SAUNDERS
http://www.angelfire.com/or/mctrl/nrpb.html

Agnes
# Posted: 3 Jul 2006 04:08
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Electromagnetic Fields and the Risk of Cancer
Summary of the Views of the Advisory Group on Non-ionising Radiation on Epidemiological
Studies Published Since Its 1992 Report
PREPARED BY J W STATHER
23 MARCH 1993
1. The first report of the Advisory Group on Non-ionising Radiation, the membership of which is given in the appendix, was published in March 1992 (1). For this report the Group reviewed the experimental and epidemiological data related to the question of electromagnetic fields and the risk of cancer. The Group concluded that the epidemiological findings that had been reviewed provided no firm evidence of a cancer risk, either to children or to adults, from normal levels of power frequency electromagnetic fields, radiofrequency or microwave radiation. The evidence strongly suggested that these radiations cannot harm genetic material and so cannot induce cancer. The only remote possibility is that they might act as promoters, that is they might increase the growth of potentially malignant cells. However, the evidence for this was considered to be weak and inconclusive, with the least weak evidence relating to brain tumours. In the absence of any unambiguous experimental evidence to suggest that exposure to these electromagnetic fields is likely to be carcinogenic, the findings could be regarded only as sufficient to justify formulating a hypothesis for testing by further investigation.
2. Since the publication of that report, a number of epidemiological studies related to the question of domestic and occupational exposure to electromagnetic fields have been issued in Sweden, Denmark and Norway. These papers have now been reviewed by the Advisory Group.
3. The Group concluded that the three new occupational studies, from Sweden, Denmark and Norway (2-4), strengthened the evidence for believing that some groups of workers in industries where exposure to electromagnetic fields may have been elevated have an increased risk of leukaemia, but not of brain cancers. No increase in the risk of leukaemia has, however, been seen in workers exposed to high levels of electromagnetic fields (1). These new studies add little to those previously reviewed by the Group. The conclusion remains that whether the hazard, if one exists, is due to exposure to electromagnetic fields or to some chemical associated with the work is impossible to decide at the present. The Group emphasised the need for research into possible occupational hazards to electrical workers based on objective measurements of electromagnetic fields and other agents, with separate examination of the risks of different types of leukaemia.
4. Two residential studies were also reviewed, from Sweden and Denmark (5,6). The Group concluded that these studies were well controlled and substantially better than those that previously reported associations with childhood cancer. However, the new studies report few cases. They do not establish that exposure to electromagnetic fields is a cause of cancer, although they provide weak evidence to suggest the possibility exists. The risks, if any, however, would be very small. In the absence of any convincing experimental support, the Group stresses the urgent need for epidemiological studies based on objective measurements of exposure to electromagnetic fields and the need to investigate further the basis for any interactions of environmental levels of electromagnetic fields with the body.
5. The recently published epidemiological studies were reviewed at a meeting of the Committee on the Medical Aspects of Radiation in the Environment held on 11 March 1993. The Committee stressed that any evidence for an association between residential exposure to electromagnetic fields and cancer was weak and based on very small numbers of cases.
6. In the UK the National Study of Childhood Cancer is examining the possible influence of a number of agents, including magnetic fields, on the incidence of childhood cancer.
7. The views of the Advisory Group have been noted in the formulation of restrictions on human exposure to electromagnetic fields developed by the Board, although at present epidemiological studies do not provide an effective basis for quantitative restrictions on exposure to electromagnetic fields.
REFERENCES
(1) NRPB. Electromagnetic fields and the risk of cancer. Report of an Advisory Group on Non-ionising Radiation. Doc. NRPB, 3, No. 1 (1992).
(2) Floderus, B, Persson, T, Stenlund, C, Wennberg, A, &0uml;st, Ä, and Knave, B. Occupational exposure to electromagnetic fields in relation to leukaemia and brain tumours: A case-control study in Sweden. Cancer Cause. Control, 4, 465 (1993).
(3) Guenél, P, Raskmark, P, Andersen, J B, and Lynge, E. Incidence of cancer in persons with occupational exposure to electromagnetic fields in Denmark. Br. J. Ind. Med., 50, 758 ( 1993).
(4) Tynes, T, Andersen, A, and Langmark, F. Incidence of cancer in Norwegian workers potentially exposed to electromagnetic fields. Am. J. Epidemiol. 136, 81 (1992).
(5) Feychting, M and Ahlbom. A. Magnetic fields and cancer in people residing near Swedish high voltage power lines. Stockholm, IMM-rapport 6/92 ( 1992).
(6) Olsen, J H, Nielsen, A, and Schulgen, G. Residence near high-voltage facilities and risk of cancer in children. Br. Med. J., 367, 891 (1993).
(7) NRPB. Restrictions on human exposure to static and time varying electromagnetic fields and radiation: Scientific basis and recommendations for the implementation of the Board's Statement. Doc. NRPB, 4, No. 5, 7 (1993).
Price £10.00
ISBN 0-85951-366-1
Last updated 4th June 1997

Source: http://www.nrpb.org.uk/Absd4-5.htm
http://www.angelfire.com/or/mctrl/nrpb.html

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