House of Commons - Science and Technology

Select Committee on Science and Technology Third Report

SCIENTIFIC ADVISORY SYSTEM: MOBILE PHONES AND HEALTH

ISSUES ARISING FROM THE GROWTH IN MOBILE PHONE USE

12. The widespread introduction of any new technology needs to be accompanied by a thorough analysis of the risks that it may pose. The scientific advisory system has a rôle to play in the identification, evaluation and minimisation of those risks. Nevertheless, by their very nature scientific advisory bodies work in areas of uncertainty. It is rarely possible to offer the clear-cut answers that Government, the press and public may seek. When associated benefits are perceived as negligible or accruing to others, the public can be intolerant of unquantifiable risks associated with new products, however negligible—as shown by the public response to the introduction of genetically modified foods. Mobile phones are seen by the public to offer a tangible and significant benefit, as the volume of sales testifies, but although benefits may offset risks, they do not eliminate them and some genuinely-held concerns remain. We recognise however that it is impossible to prove a negative. No matter how much research is done, it will never be possible to prove that something is not harmful. Scientific research can say that there is no evidence of risk or it can demonstrate that any risk is very low, but it cannot produce evidence of no risk. Nevertheless, in contrast to the negative impact of concerns about the safety of genetically modified food on sales, media stories highlighting possible hazards associated with the use of mobile phones have not prevented high sales growth. Public hostility is more often directed against transmitter masts in residential areas.

Perceived Health Hazards

IONISING AND NON-IONISING RADIATION

13. The electromagnetic spectrum ranges from high-frequency gamma rays at one end to low frequency radio waves at the other. Radiation at high frequencies can break down chemical bonds and is known as ionising radiation. In biological tissues this may cause damage to deoxyribonucleic acid (DNA)[14] and can lead to cancer. On the other hand, RF radiation, including microwave radiation, has much lower frequencies and is termed non-ionising radiation; because the lower energy levels associated with RF radiation are insufficient to break chemical bonds, they are not a health threat through ionisation.[15] We are all regularly exposed to RF radiation from a variety of sources. Besides mobile phone systems, common sources of radio waves include television broadcasts which in the UK operate at frequencies between 400 MHz and 860 MHz and microwave communication links (dishes) which operate at frequencies above 1000 MHz.

THERMAL EFFECTS OF NON-IONISING RADIATION

14. Microwave radiation can cause heating in biological tissues in much the same way as food is heated by a microwave oven. This thermal effect of microwave radiation can cause disruption to biological processes and tissue damage if the intensity is too high. The intensity of radiation from mobile phones is a small fraction of that emitted by microwave ovens, which typically operate at a frequency around 2450 MHz, but the radiation is directed to the head when the phone is held to the ear in normal use. The current guidelines for maximum exposure to microwaves are intended to avoid harmful heating from the phones or the masts. Under existing regulations, all phones on the market are required to emit microwaves at an intensity low enough to avoid causing a damaging level of localised heating. Similarly, the transmitter bases are required to emit microwaves at an intensity low enough to avoid causing a damaging level of total body heating in humans who pass by the masts. Patterns of mobile phone usage have, however, altered since the guidelines were established. It has been suggested that as mobile phones are now used for sustained periods, "the question of length of exposure may need to be considered as a factor in determining whether such exposures could be harmful".[16]

ATHERMAL EFFECTS OF NON-IONISING RADIATION

15. Some concerns which have been raised do not relate to the known and relatively well-understood heating caused by microwave radiation but rather to possible so-called 'athermal' effects. Some studies have shown that RF radiation may have other biological effects, for example on brain tissue and the immune system, and transient effects on behaviour. The biological significance of such effects is as yet unclear;[17] and there is no conclusive evidence to show that these effects operate in the whole organism.

The Regulatory and Advisory Rôles of Government

16. The 'precautionary principle' is recognised by European Governments in the Maastricht Treaty and forms the basis of both EU and UK regulation in this area.[18] Under a strict application, it would not be possible to balance the risks of harm with the benefits of technological advances, since even a small degree of uncertainty or a suspicion of possible harm, no matter how ill-judged, would be enough to prohibit the introduction of a new technology. This interpretation is not, however, sustainable; it would preclude the application of almost any significant development as almost all innovations may have hidden or unknown risks. In practice, therefore, applying the precautionary principle means measures must be taken to minimise known risks and alertness to the emergence of unknown risks must be maintained.

17. Regulation of the mobile phone industry rests with the Department of Trade and Industry (DTI), which has the responsibility for licensing the network operators under the Telecommunications Act 1984 and also for the safety of consumer products while the Department of Health is responsible for protecting public health. Licensing of mobile phone operations is not, however, conditional on compliance with any radiation safety standards.[19] Under the General Product Safety Regulations 1994 it is an offence to supply unsafe consumer products.[20] These regulations are enforced by local authority trading standards officers who have the power to remove unsafe products from sale. Safety assessments of mobile phones take maximum microwave exposure guidelines into account.[21] Protection of people at work (and the public as a result of work activity) against possible health impacts of mobile phones and their masts is the responsibility of the Health and Safety Executive (HSE). The HSE makes no distinction between the occupational and social use of mobile phones in terms of health, so its prime responsibility is to assess any risk posed to workers or the public by transmitter masts.[22]

18. The Rt Hon Ms Tessa Jowell MP, Minister for Public Health, and the Department of Health have responsibility for providing advice on the possible health impacts of mobile phones.[23] Government's principal source of scientific advice on the health impacts of mobile telephony is the National Radiological Protection Board (NRPB).[24]

Maximum Exposure Guidelines

19. The Government recognises guidelines for maximum exposures to microwaves established by the NRPB. These are defined in terms of the maximum energy that can be safely absorbed by a given mass of tissue, otherwise known as the specific energy absorption rate (SAR) and are set at a level designed to prevent any adverse effects from heating.[25] The current NRPB guidelines, established in 1993, stipulate a maximum SAR of 0.1 watts (W) in any 10g of tissue for exposure to the head and 0.4 W/kg for whole body exposure.[26] They are based on the most recent report concerning radiation at mobile phone frequencies from the NRPB's Advisory Group on Non-Ionising Radiation (AGNIR).[27] Other countries operate different, more conservative, guidelines for maximum microwave exposures. For example, the maximum SAR recommended in the USA is 1.6W/kg for exposure to the head.[28]

EU Health Council Recommendation

20. On 8^th June 1999 the European Union (EU) Health Council agreed a recommendation, with the support of the UK Government, for limiting exposure to electromagnetic fields thereby establishing, for the first time, EU-wide safety standards for mobile phone emissions.[29] The recommendation was based on the exposure limits recommended by the International Commission on Non-Ionising Radiation Protection (ICNIRP), an independent international body of experts on electromagnetic fields and health.[30] The recommendation proposes limiting public exposure to an SAR of 0.2W per 10g of tissue for the head and 0.08W/kg for the whole body (one fifth of the exposures permitted by the NRPB's guidelines) whilst permissible occupational exposure would remain at the level defined by the NRPB.[31] The recommendation has no effect in law and the Minister told us the Government would not automatically adopt matching guidelines for exposure limits in the UK but would "allow the NRPB to consider the standards, to provide advice and then have proper consideration".[32]

21. The ICNIRP guidelines include a "reduction factor" of five in maximum SAR for the public as opposed to occupational exposure. The NRPB argues that "there is a lack of scientific support for the introduction and choice of these reduction factors" and that the existing UK guidelines of limiting exposure of the public "provide adequate protection ... the health benefits to be obtained from further reductions in exposure have not been demonstrated".[33]

22. The current guidelines for maximum SARs for mobile phones were established before the major increase in frequency and duration of use was envisaged and this has led some to suggest that the NRBP guidelines should be revisited.[34] We agree with the NRPB that there is no validated scientific evidence to justify lower exposure limits. Nevertheless, the extent to which many, including the NRPB itself, are calling for more research, particularly in the area of athermal effects of microwaves, justifies a precautionary reduction in maximum exposure guidelines.[35] As the Minister pointed out, the impact on the industry would be a factor in the Government's decision on whether or not to adopt the EU guidelines. Motorola told us that the EU limits had been expected for some time and therefore many parts of the industry already complied.[36] Similarly, Vodafone told us that they thought that "pretty well all cell sites in the UK will comply today".[37] Therefore, although there is no scientific evidence to indicate significant health risks, we recommend that the Government adopt the ICNIRP recommended guideline limits for microwave exposure as a precautionary measure. We further recommend that these guidelines be introduced quickly but with a grace period to allow network operators to achieve full compliance.