HC Deb 29 October 1998 vol 318 cc530-8

Motion made, and Question proposed, That this House do now adjourn.—[Mr. Kevin Hughes.]

8.11 pm
Miss Anne McIntosh (Vale of York)

I am grateful for the opportunity to have this debate. I am sure that the House will join me in congratulating the Minister for Public Health, who has today been appointed a Privy Councillor.

I shall explore the dangers to health caused by exposure to electromagnetic fields near power lines. In preparing for the debate, I was immensely grateful to be able to consult the work of Professor Denis Henshaw at the university of Bristol, which is entitled "Mechanisms of increased exposure to environmental pollutant aerosols near high voltage powerlines"; the work of Professor Mike O'Carroll, emeritus professor at the university of Sunderland and chairman of Rural England Versus Overhead Line Transmission, otherwise known as REVOLT; and the report of the working group of the United States National Institute of Environmental Health Sciences entitled "Assessment of Health Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields".

All that work proves that there is a strong possibility that electromagnetic fields contribute to cancer in those living near overhead power lines. In those circumstances, I am calling on the Minister to comment conclusively on the health aspects. If I were her, I would not want on my conscience any negative effects of a newly proposed giant, high-voltage power line between Lackenby and Shipton via Picton through the Vale of York. I hope that an element of doubt will be raised this evening sufficient to delay the construction of that line until the health aspects have been fully explored.

House of Commons research paper 94/119 of 24 November 1994, entitled "Overhead Power Lines and Health", takes up the suggestion that exposure to electromagnetic fields near overhead power lines may increase the risk of contracting cancer. It examines scientific evidence for such a link. It summarises the relevant exposure restrictions recommended by the National Radiological Protection Board, based on established health effects arising from exposure to electromagnetic fields and radiation.

Electricity and magnetism are different aspects of the same physical phenomenon. They are natural processes that are seen in thunderstorms. The earth has a steady, static electric field arising from electrically charged atoms and molecules in the atmosphere. The strength of this electrical field near the ground is about 120 volts per metre. That is a measure of the force that would be exerted on an electrically charged particle placed in the region of space permeated by the field. Electrical currents below the earth's crust give rise to a magnetic field. The direction of that field is determined by the force that it exerts on a compass needle.

Teslas give magnetic flux density—the common measure of strength of magnetic fields. The House of Commons research paper gives the power frequency magnetic flux densities at various distances from various household appliances. At 3 cm from a hair dryer, the magnetic flux density in microteslas falls within the range of six to 2,000 microteslas. At 30 cm from a hair dryer, it falls between 0.01 or less and 7 microteslas. At 3 cm from a gentleman's electric shaver, it falls between 15 and 15,000 microteslas. At 1 cm from an electric overblanket, it falls between 2 and 3 microteslas.

On 10 June 1997, the Minister replied to a written question on potential health risks posed by mobile phone usage and the use of electric blankets. She said: The Department obtains advice from the National Radiological Protection Board … on the risks to health of exposure to electromagnetic fields. The NRPB's advice is based on … scientific studies … carried out by the World Health Organisation, by the NRPB Advisory Group and others. She said that NRPB's advice is that there is no convincing scientific evidence that exposure to microwave radiation associated with mobile phone and electric blanket usage is harmful to … health."—[Official Report, 10 June 1997; Vol. 295, c. 422.] I ask the House to contrast that decision on so-called inconclusive scientific evidence with the decision taken by the same Government—albeit a different Department, the Ministry of Agriculture, Fisheries and Food—to ban the sale of beef on the bone. Why and how did the same Government jump to ban beef on the bone with much less available evidence than we have of the dangers from electromagnetic fields? The Government are quick to act at one level and ban beef on the bone on the basis of inconclusive scientific evidence, whereas they are reluctant to act on the threat to health, particularly children's health, from exposure to electromagnetic fields near overhead power transmission lines.

Ms Sally Keeble (Northampton, North)

I congratulate the hon. Lady on securing this important Adjournment debate. I also congratulate the Minister on her appointment.

Is the hon. Lady aware that there is a cluster of families in my constituency whose children have had childhood leukaemia, two of whom tragically died? Is she also aware that Professor Henshaw is coming this weekend to look at the impact of power cables that are above the ground and close to the railway lines behind their homes, and to consider the possible role that electromagnetic fields from those power cables may have played in causing the children's illness?

Miss McIntosh

I am indeed. I am grateful to the hon. Lady for raising that issue. The House and the Minister will have cause to be grateful to Professor Henshaw for his studies. I hope that some good news follows from his visit to the hon. Lady's constituency.

The Government and the National Grid will argue that the proposed line through the Vale of York and elsewhere in North Yorkshire does not pass through centres of population. That is not strictly correct. Certain stages near the start of the line go through residential centres. Even in the Vale of York, the lines pass within a mile of a village or the outskirts of a town.

I believe that the Government need to develop a systematic approach to hazards whose effects are not precisely known and will become clear only over time. Although the scientific evidence may not be conclusive, it is sufficient to raise questions and concern and, in my view, to justify a delay in the construction of any further power lines until the full effects are known. The term "prudent avoidance" is often used by the United States Government in relation to possible health hazards. Although the Government will not legislate, they will advise people to avoid the dangers.

Two possible links with cancer arise from such hazards: energy effects—electromagnetic, for instance—and information effects, interfering with the body's chemical and hormonal systems. In June 1998, the United States published a report produced by the National Institute of Environmental Health Sciences, which I have with me this evening. It is important, in that it reinforces the view that power lines are a possible cause of cancer. If the Minister reads no other part of the report, I strongly urge her to read page 396, and, in particular, the conclusion that carcinogens may be caused in humans by power lines. The report states: electric and magnetic fields such as from powerlines are a possible human carcinogen". That statement is accompanied by a 500-page report, which is widely available on the internet. Distinguished scientists from Sweden, France and Italy participated.

The report raises the question of planning in relation to houses near power lines, and it is bound to have an impact internationally. Notably, and regrettably, no United Kingdom expert participated in the study that produced it. Is the Minister aware of that study, and of its wide health implications?

Research based at the university of Bristol under Denis Henshaw, professor of physics at the university, is concentrating on trying to find a causal mechanism to explain the acknowledged increase in the incidence of leukaemia under high-voltage power lines. Professor Henshaw is now aware of five separate mechanisms through which the electric field from power lines interacts with airborne pollutants in a way that leads to increased exposure near power lines. Childhood leukaemia is known to be associated with airborne traffic pollution, and the Bristol university hypothesis is based on increased exposure, under power lines, to an agent that is already firmly linked to childhood leukaemia.

The research has progressed as far as demonstrating increased exposure to an agent—traffic pollution—that is known to be linked to childhood leukaemia; but the general concern at Bristol university about the health effects of living under power lines goes well beyond the childhood leukaemia risk. I wonder whether the Minister is aware of the work conducted by Professor Henshaw and his team.

Another question is how far housing developments should be from a 400,000-volt power line. Given the existence of continuous and increasing exposure to environmental pollutants, 20 m is far too close. Epidemiology demonstrates that the preferred distance is 100 m. However, an unpublished report by the United States National Council on Radiological Protection in 1990 made a recommendation stating that being 150 m from overhead power lines was potentially dangerous. Does the Minister agree with that analysis?

Although the power lines that are to be built through the Vale of York from Lackenby to Shipton via Picton will not go through a large centre of population, they will nevertheless pass by such centres, and over many hamlets and large farm dwellings. Does the Minister, as a Public Health Minister, really want on her conscience the remotest possibility of the formation of clusters of cancer, such as leukaemia, which could be related to the new giant transmission line that the Government have allowed?

I invite the Minister to consider the weight of the evidence, to operate the policy of "prudent avoidance" that exists in Sweden and part of the United States, and to delay the construction of any further power lines until more is known about their health effects and potential risks. Finally, may I ask whether she will agree to a moratorium on the building of any more power lines at this time?

8.25 pm
The Minister for Public Health (Ms Tessa Jowell)

I join my hon. Friend the Member for Northampton, North (Ms Keeble) in congratulating the hon. Member for Vale of York (Miss McIntosh) on securing a debate on an issue that is extremely important to her constituents, and in regard to public health more generally.

Let me give some of the background. The decision to grant consent for the building of the North Yorkshire lines was made in March this year, following public inquiries in 1992 and 1995. The then Secretary of State for Trade and Industry concluded: in the absence of any material change in the evidence of any harmful effect from electric and magnetic fields emitted by power supply equipment, possible health effects provide insufficient grounds to refuse consent to the development. The issue applies not only to the Vale of York, but to any part of the country where people are concerned about power lines.

We are exposed to electromagnetic fields every day in many different ways, at home and at work. Kitchen appliances, computer screens in offices, security systems in shops and airports and the networks of power transmission lines and radio and television stations all emit those fields. Industry, transport and defence networks, and hospitals depend on electrical equipment emitting EMF in one form or another. It must be recognised that EMF can never be completely avoided. Electromagnetic fields also occur naturally. The earth produces natural fields: magnetic fields at the earth's surface are produced by electric currents flowing deep within the earth's core. Electric and magnetic fields are also produced in the atmosphere. The strength of those fields changes with weather conditions; that excludes the massive effects of lightning strikes. Electrostatic fields are not uncommon, and can be encountered from charged objects in the home and at work.

During the 20th century, environmental exposure to man-made EMF has increased steadily owing to the demand for the provision and consumption of electricity, advances in technology and changes in social behaviour. In the 1960s and 1970s, the main concerns involving power lines were to do with their aesthetic impact, their interference with radio or television reception and problems with noise and perception.

In 1979, concern about the alleged link between cancer and public exposure to magnetic fields arose because of an American study of the incidence of childhood cancer in Denver. That study, and the public and media interest that it created, stimulated much of the scientific research that followed. The hon. Lady has outlined the range of conclusions that that research has produced.

Since then, many human health studies have been published around the world. Some of them have found an increased incidence of illness in people living close to power lines, but other studies have not. However, it should be noted that the risk, where it has been quantified, is usually small.

A great deal of attention, usually by the media, may be given to a study that suggests a health risk, despite the large number of other studies that do not suggest such a risk. In considering important public health issues, it is important that the balance of risk is made clear.

Currents produced in the body from electromagnetic fields near power lines are weaker than natural currents in the body, such as those produced by the brain and heart, so some scientists argue that it is impossible for EMF to have any important effects. Other scientists argue that, just as a trained ear can pick up a familiar voice or cry in a crowd, so a cell in one's body may respond to induced current as a signal that is lower in intensity yet detectable even through the background noise of the body's natural currents.

Laboratory studies, often using high-intensity electromagnetic fields—higher than those to which we are normally exposed—have shown that some biological effects can be caused by exposure to EMF. However, biological effects do not necessarily translate into health effects—an important distinction. In most cases, it is not clear how EMF produces those demonstrated biological effects; in particular, no mechanism has been established for possible carcinogenic effects.

Some biological effects are well known. Strong electric fields, such as those beneath large transmission lines, can cause hair on the exposed head or arms to vibrate slightly. That is felt by some people as a tingling sensation. EMF from transmission lines can also, in some circumstances, cause nuisance shocks from voltages created by EMF on objects or metal structures, such as fences.

Miss McIntosh

I have some difficulties with the Minister's arguments, for reasons that I hope that she will understand. I believe that any death caused by living too close to a power line carrying high-voltage electricity is one death too many. Does her Department have a formula, such as the one used by the Department of the Environment, Transport and the Regions to establish how many deaths there have to be before a roundabout is built? Why is it more acceptable for a pylon to pass within 20 m or 100 m of a dwelling that houses 10 people than for a pylon to pass close to a housing development?

Ms Jowell

Risk assessment is an extremely important way in which to make judgments about difficult and contentious public health issues. It is also an important and vivid way in which to convey information about risk to the public. However, it is a developing science and, although we can use calculated risk assessment to demonstrate the harm that some actions may cause, we cannot yet use it with scientific certainty as the sole guide in making decisions that may also, for example, involve planning considerations.

Last year, the hon. Lady took part in a debate about the siting of electric pylons in her constituency; the issues that she raised were primarily environmental rather than health related. Of course, our overriding concern is to protect the public's health and to prevent death, but the means of conveying risk levels is difficult. I do not believe that the methodology is sufficiently developed to be used as the sole basis for making such decisions, which is why we rely so heavily on the expert advice of scientists who are qualified in this field.

Before I set out some of the more detailed scientific background that informs Government policy, I shall say something about the guidelines on exposure restriction. At relatively high EMF intensities, there are short-term immediate health effects—including subtle effects on the nervous system—against which people need to be protected. For some types of EMF, such as microwaves, the main effect is the heating up of tissues in the body.

Those well-established effects have been thoroughly studied and documented for many years, and guidelines have been published on the exposure limits that may prevent such effects. Although the restrictions need to be considered only in industrial premises using high-intensity EMF, it is also important that people are given proper guidance about protection in their homes.

In the United Kingdom, guidance on the levels of exposure restriction is obtained from the National Radiological Protection Board, an independent body that was set up under statute to provide radiological advice. Industry and planners currently follow those guidelines to protect workers and members of the public. Discussions are under way to harmonise guidelines throughout Europe based on the recommendations of the International Commission on Non-Ionizing Radiation Protection, an organisation comprising individuals from many countries with expertise in the effects of EMF.

Both those bodies, along with the World Health Organisation, have looked long and hard into the scientific data on which they will base their guidelines. All have agreed that the available data on potential long-term effects, such as cancer, are insufficient to provide a basis for setting exposure conditions.

In 1992, the overall position was summed up in a review of the published literature by the NRPB's advisory group on non-ionising radiation. The advisory group concluded that there was no firm evidence of a carcinogenic hazard from exposure that could be associated with residence near major sources of electricity supply, the use of electrical appliances or work in the electrical, electronic or telecommunications industries. The independent advisory Committee on Medical Aspects of Radiation in the Environment endorsed the advisory group's report.

The advisory group's position was mirrored in the US by the National Academy of Sciences, which undertook a similar review in 1997. A more recent epidemiological study of childhood cancer by the US National Cancer Institute produced results that, using the authors' own words, can be summarised as "reassuring rather than alarming".

Very recently, the National Institute of Environmental Health Sciences working group voted, by majority, that EMF should be treated as a "possible human carcinogen", a definition that appears to be based on a recognised category laid down by the International Agency for Research on Cancer. The proposal is at public consultation stage, and a final report is due to go to Congress before the end of 1998.

Despite the reassurances of some of the reviews and statements, there clearly remains widespread concern. Moreover, the positive association from a few studies suggests that there is good reason to continue to investigate the issue both experimentally and epidemiologically. Indeed, all the bodies—and we ourselves—agree that more work needs to be done to shed light on the issue and create the greater basis of certainty that we all want.

Miss McIntosh

There was inconclusive evidence for the ban on beef on the bone, and many would say that the weight of evidence was in favour of continuing to sell it. I do not see the logic of banning beef on the bone, but allowing what is clearly a health risk to continue. There could well be evidence of that risk in the Minister's constituency.

Ms Jowell

That is an important point. Risk assessment—knowing what the odds are—takes us part of the way, but does not provide us with the definitive basis for action. Beef on the bone was banned because of the judgment that there could be a risk of a further opportunity for BSE, in the form of new variant CJD, to be transmitted into the human food chain, not only through eating beef, but through eating stocks, broths, soups and other preparations made from bones that might have been contaminated.

We considered carefully the Spongiform Encephalopathy Advisory Committee's advice on that and on other aspects of BSE, and our efforts to understand more about new variant CJD—a devastating disease about which we know so little—and, from a public health point of view, we considered it essential to close every possible window of opportunity for further contamination or further infection of humans with the properties that translate into new variant CJD.

I reiterate the clear view that there is a need for further research to allay public concern. The positive association from a few studies suggests the need for further investigation. A number of human health studies have been carried out, especially in Europe and North America, and more are under way. Most of the emphasis has been on cancer. A few of the studies suggest that exposure to low levels of EMF may cause some effect, but those findings have tended to be weak and inconsistent, and other studies suggest no increased risk of the disease. Until now, most scientists and clinicians have agreed that the health effects of low-level EMF are likely to be very small, if they exist at all.

Experiments with healthy volunteers clearly show that short-term exposure at the levels experienced in the environment or in the home do not cause any clinical or pathological effects. Some studies report effects, but they tend to be inconsistent between studies. Many animal and cellular studies have failed to show any significant effects of exposure. Reported effects tend to be small and experiments must be performed with great care for any effect to be detected.

A great deal of effort is being directed towards investigating the effects of magnetic fields on cancer. It seems that magnetic fields alone cannot cause cancer, although some laboratory studies suggest that they speed up the development of existing cancers.

In 1996, the international EMF project was initiated by the World Health Organisation. The project will assess health and environmental effects of exposure to time-varying electromagnetic fields. The project is being carried out in collaboration with national and international agencies, organisations and research institutions. The Department of Health is contributing to the funding of this large undertaking, as is the Health and Safety Executive.

The NRPB, which is highly regarded throughout the world for its expertise in the field, is an official collaborating institution with the WHO EMF project. Many international organisations are involved and a series of international seminars is being held where leading scientists present status reports on dosimetry, in vitro, in vivo and human studies. The project will publish environmental health criteria monographs of the scientific literature towards the end of the five-year programme.

The Department of Health also supports the United Kingdom childhood cancer study, a key study due to report next year. The study was set up in 1992 and is the largest of its type. It is investigating cases of childhood cancer for which the causes are still unknown. EMF is one of a number of possible causes included in the study. The Department also supports another type of epidemiological study of childhood cancer and some biological laboratory work. Results will be published in the scientific press when the studies are complete.

Researchers at Oxford university have been investigating the effects of EMF on free radicals in the body. Others, such as Professor Henshaw at Bristol university, have proposed the idea that electric fields attract very small particles such as bacteria, thereby increasing the likelihood of disease in their vicinity.

I hope that that makes it clear that we are faced with scientific data that produce a range of conclusions. The way in which we act on those conclusions is to subject the analysis to scrutiny by the experts on the NRPB. The hon. Lady raised several important points about the continuing uncertainty. The development of risk assessment, the application of best available evidence and the continuing search for greater certainty will guide what we do. We will ensure that the conclusions are published and that the process by which our decisions are reached is transparent. Ultimately, our overriding concern will be the protection of public health and safety.

Question put and agreed to.

Adjourned accordingly at twelve minutes to Nine o'clock.