FAQs – TETRA and Health

Is there any evidence that TETRA affects health?

There has been a substantial amount of research into the effects of radio frequency emissions, including the frequencies used by TETRA, over a number of years. The balance of scientific evidence does not demonstrate any link between radio frequency emissions at levels below the safety standards and adverse effects on health. In its 2007 report MTHR said “Mobile phones have not been found to be associated with any biological or adverse health effects.”

Professor Colin Blakemore, head of the Medical Research Council and a Stewart Inquiry Committee member, has said “nobody has established a medical risk and on balance there is no real reason to worry about TETRA. It is certainly no greater risk than a mobile phone…… “.

The MTHR Report published in 2007 said that none of the research supported by the programme and published so far had demonstrated that biological or adverse health effects are produced by radiofrequency exposure from mobile phones.

Does TETRA affect the functioning of the brain?

Cognitive studies with volunteers exposed to RF from TETRA handsets whose performance in various cognitive tests – including speed of reaction, short term working memory and sustained attention – found no impact of the TETRA signal.

In its 2007 report, MTHR said “Studies on volunteers….. showed no evidence that brain function was affected by mobile phone signals or the signals used by the emergency services (TETRA)”.

Does TETRA have an impact on heart rate or blood pressure?

A volunteer study undertaken by the University of Sheffield using both GSM and TETRA signals investigated whether exposure to the RF signals caused changes in heart rate or blood pressure and also measured levels of adrenaline in the bloodstream, No changes in heart rate, blood pressure or blood chemistry were observed. The findings were published in Bioelectromagnetics 2007 28(6):433-438.

To read a summary of a presentation about this study given by Professor Tony Barker at a THG seminar in 2008 click here (opens in a new window).

Does TETRA have an adverse impact on people who say they are hypersensitive to RF?

The HPA published a review of the literature on electro-sensitivity in November 2005 – to read the report click here.

The review stated that the use of the term ‘electrical sensitivity’ did not imply acceptance of a causal relationship between symptoms and attributed exposure.

The HPA conclusion is consistent with the WHO view as expressed following the Prague workshop in October 2004, which can be summarised as:

  • electro-sensitivity is characterised by a variety of non-specific symptoms.
  • while the symptoms are real, there is no scientific evidence of a causal link – more than 30 studies have failed to demonstrate a relationship and the evidence is that fields from base stations cannot affect molecules of biological tissue.
  • there is no indication that making the international standards more stringent would reduce such symptoms.

As part of the MTHR programme there is are studies in progress on perceived hypersensitivity to handsets at Kings College London and on perceived hypersensitivity to TETRA base station signals at the University of Essex. To learn more about these visit our Science page, or click here to see a summary of presentations on these studies made at a THG seminar in 2008 (opens in a new window).

Are there potential longer term effects?

This is currently a difficult question to answer as mobile phone and TETRA technology is relatively new and there are no complete long-term epidemiological studies. However, experts believe that there are no additional risks from use of TETRA compared with use of mobile phones or analogue police radios, and point out that the latter have been used for something like 30 years without an impact on health.

Why can’t scientists say categorically that TETRA is safe?

Science cannot prove categorically that something is safe; the only certainty in science is that there is no certainty. It is not possible to prove a negative, so no-one can prove conclusively that a product or technology is not harmful. Scientific methodology is empirical. Knowledge develops from observation and measurement, producing theories that can be used to predict what might happen under certain conditions, testing those theories through experiments and studies, peer-reviewing the findings, methodology, and conclusions, and attempting to replicate the results. In this way a body of robust scientific evidence builds up. If, after many years, a number of studies find no harmful effects, scientists can say with growing confidence that a product is probably safe.

The World Health Organisation holds a database of hundreds of studies into the impact of radio frequency emissions, including some at the frequencies used by the TETRA standard. The balance of evidence has demonstrated no adverse impact on health. While uncertainties remain about the potential effects of long-term use of radio-based technologies, advisory bodies like the World Health Organisation advocate a precautionary approach. However, this does not mean that radio technologies should not be used and it reaffirms the importance of science-based standards.

Is it safe to use a TETRA handset when pregnant and is there any effect on the incidence of breast cancer?

The 2004 AGNIR report concluded that there was no evidence that TETRA caused DNA mutation or promoted the formation of tumours. The epidemiological evidence does not show a link to an increased incidence of breast cancer. There is limited evidence on use in pregnancy but AGNIR looked at early miscarriage and congenital malformations and found no evidence of any effect.

Does TETRA have any effect on fertility?

There is little epidemiological evidence on this but if a TETRA radio is worn in its correct position on the abdomen (for example on a belt) the distance of the radio from the sex organs would mean that the RF would be minimal, so experts judge this unlikely to have any effect.

As TETRA handsets pulse can they cause epilepsy in a similar way to pulsing light?

This is most unlikely because the human eye is not sensitive to RF in the way it is sensitive to light, and no biological mechanism exist for the eye to transmit information about RF directly to the brain as it does with light.

What is the difference between a biological effect and a health effect?

We need biological effects to function. All our senses rely on biological effects – for example our eyes need light to see. If the intensity of the biological effect is above a safe threshold value then it can become a health impact. To continue with the analogy of eyesight this would be staring directly into the sun or having a laser shone into our eyes. So a biological effect is not of itself a health issue.

Is there a link between TETRA and cancer?

In its 2007 report MTHR said that a six year research programme had found no association between short term exposure to radio frequency emissions and brain cancer. However, symptoms from many diseases, including cancer only become apparent years after the event that produced them, so the report recommended long-term research.

What is the effect of heat penetrating the head when a handset is used?

Biological material is weakly conductive to heat. The heating effect would be a maximum of one twentieth of a degree centigrade in 6 minutes. In practice the effect would be less, as the power is often reduced by adaptive power control, and transmissions are very rarely as long as six minutes. Human body temperature varies during the day by around one degree centigrade so most people believe there is no impact on health caused by heating. If users hold the handset against their face they may feel some warmth but this is caused by the battery in the handset being slightly warmer than room temperature, and not by radio frequency emissions.

Will the use of ElectroDOT on TETRA terminals help mitigate the impact of radio frequency emissions on users?

From time to time a number of different products come onto the market making various claims about providing protection against radio-frequency or electrical emissions.

All the terminals and equipment manufactured and supplied by members of the TETRA Health Group comply with international guidelines that are fully supported by robust and rigorous scientific research and endorsed by the World Health Organisation (WHO). The members of the group do not therefore endorse the use of ElectroDOT or similar products.

ElectroDOT claims to combat ‘electro-pollution’ by adjusting the ‘vibes’ or emissions from electrical equipment. To the best of our knowledge there has been no independent scientific or health study to review these claims. Expert advice suggests that the alleged health effects that the product seeks to negate are not recognised by science and that the way the device operates does not seem to be based on the laws of physics.

An article in the Irish Times on Tuesday 31 March 2015 suggested that the Association of Garda Sergeants and Inspectors, and individual Garda staff, had questioned the safety of TETRA hand-held terminals, in particular, is there an additive effect when used inside a vehicle or within a police station?

There is a wealth of peer-reviewed research concerning the radio-frequency emissions from handsets and whether this poses any health risk, and about whether using a handset or multiple handsets within a vehicle increases the exposure and hence the risk. Examples of the research available include studies which measure the radio-frequency emissions from handsets and compare them with international guidelines which measure the emissions from aerials used on cars and motor-cycles, and those from using multiple handsets within a vehicle.

The results of all these studies suggest that there is very little cause for concern. No additive effects have been found.

Dr Phil Chadwick has researched the effects of using TETRA terminals in vehicles and his full report can be found here (opens in new window). A presentation given by Dr Chadwick at a THG seminar in 2007 can be found here (opens in a new window).

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