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NRPB limits 2004
NRPB Advice on limiting exposure to EMFs
Until 2004, the NRPB published its own exposure
guidelines. In March 2004, it recommended instead that the UK
should adopt the ICNIRP
guidelines. It actually published two documents:
Advice
on Limiting Exposure to Electromagnetic Fields (0-300 GHz)
Review
of the Scientific Evidence for Limiting Exposure to Electromagnetic
Fields (0-300 GHz)
In July 2004 the NRPB also published a
Summary of comments received on the May 2003 Consultation Document
and responses from NRPB
see also more on exposure limits
generally and on previous NRPB statements
Differences between ICNIRP and NRPB
The NRPB and ICNIRP guidelines are the same for occupational exposure.
The main difference is that for the public, the ICNIRP levels are
a factor of five lower.
NRPB states:
“The review of current scientific knowledge by NRPB staff,
the adoption of a cautious approach to the interpretation of these
data, and a recognition of the benefits of international harmonisation,
combine in the Board’s recommendation to adopt the ICNIRP
exposure guidelines for occupational and public exposure to EMFs
between 0 and 300 GHz (ICNIRP, 1998).
“The detailed scientific analysis by NRPB staff supports
the recommendation by ICNIRP that exposure guidelines for members
of the public should be more restrictive than for workers. This
allows for a greater sensitivity to adverse health effects in
the general population than for the working population. Increases
in sensitivity may occur in infants and children, individuals
being treated with medication, and those in the later years of
life. The ICNIRP recommendation of a reduction factor of five
in the basic restriction for members of the public compared with
workers is appropriate.”
The values
| |
1993 NRPB Guidelines
(the same for occupational and public) |
1998 ICNIRP Guidelines |
| Occupational |
Public |
| Basic Restriction(the quantity which must not
be exceeded) |
Induced current density in the central nervous
system |
10 mA m-2 |
10 mA m-2 |
2 mA m-2 |
| Reference Level(not a limit in itself
but a guide to when you need to investigate the basic restriction)
|
Magnetic field |
1600 µT |
500 µT |
100 µT |
| Electric field |
12 kV m-1 |
10 kV m-1 |
5 kV m-1 |
Effects considered in providing advice
Both the NRPB and ICNIRP levels are chosen to prevent fairly well-established
effects of EMFs on the body (at power frequencies, the effect on
induced currents on the central nervous system). NRPB state:
“It is concluded that there are scientific data indicating
the need for appropriate values for restrictions on exposure.
These data derive from experimental studies related to effects
of EMFs on the central nervous system… The restrictions
on exposure and recommendations for further investigation, where
relevant, are derived from data on these effects.”
But in arriving at these recommendations, NRPB also reviews the
evidence for the whole range of other possible effects of EMFs.
It concludes:
“Evidence of other possible effects associated with EMF
exposure derives principally from epidemiological studies and
from some experimental studies. The main, but not sole, subject
of such studies has been cancer. These studies have been reviewed
extensively by expert groups, including AGNIR, and are summarised
in the associated review of the science (NRPB, 2004). It is concluded
that currently the results of these studies on EMFs, taken individually
or as collectively reviewed by expert groups, are insufficient
either to make a conclusive judgement on causality or to quantify
appropriate exposure restrictions.”
NRPB recommendations on precaution
However, although NRPB concludes these studies do not justify quantitative
exposure limits, it does suggest they may justify considering precautionary
approaches.
The summary Statement says:
“An association between prolonged exposure to intense power
frequency magnetic fields and a small raised risk of childhood
leukaemia has, however, been found, the scientific reasons for
which are presently uncertain. In the light of these findings
and the requirement for additional research, the need for further
precautionary measures should be considered by government.”
The main body of the document states:
“There remain concerns about the possible effects of exposure
of children to power frequency magnetic fields. The view of NRPB
is that it is important to consider the possible need for further
precautionary measures in respect of exposure to children to power
frequency magnetic fields.”
“The government should consider the need for further precautionary
measures in respect of exposure of people to EMFs. In doing so,
it should note that the overall evidence for adverse effects of
EMFs on health at levels of exposure normally experienced by the
general public is weak. The least weak evidence is for the exposure
of children to power frequency magnetic fields and childhood leukaemia.”
more on precaution generally.
The legal position
The NRPB’s role is to provide advice to Government. Its advice
does not have direct force on either industry or the public.
In August 2004, in response to the NRPB’s recommendation,
the Parliamentary Under Secretary for Public Health (Melanie Johnson)
wrote to the Chairman of the NRPB welcoming the new advice. The
letter included a
10
point annex describing the way Government intends to implement
the NRPB advice. It points to the need for inter-departmental working
and introduces the initial plans for a wider stakeholder process
in order to consider the possible need for further precautionary
measures in respect of extremely low frequency (ELF) electromagnetic
fields (EMF).
The key statement about implementation is:
“… the Government expects the NRPB guidelines to be
implemented in line with the terms of the EU Recommendation, that
is, taking account of the risks and benefits of action. Preliminary
discussions have already taken place to identify what reasonable
actions might be taken.”
On precautionary measures, it says:
“The Government will be exploring further the practical applications
of precautionary measures within a stakeholder engagement process.
This will be the subject of wide consultation and will explore any
risks and benefits arising in the same manner as a Regulatory Impact
Assessment.”
Consultation on NRPB revision
The NRPB embarked on its review of its exposure guidelines in 2002.
It conducted a consultation with selected individuals in Autumn
2002 and held a public meeting in December. On 1 May 2003 it published
a consultation document on its web site with the public consultation
period running till 28 July. The document proposes the adoption
of the ICNIRP exposure guidelines.
The UK electricity industry response to the consultation is available
here.
Links to responses by other groups and individuals that we are aware
of and are available on the internet are in links.
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