RADIATION MATTERS
As already foreshadowed, concern about health and safety associated with
uranium mining and milling overwhelmingly focussed on the hazards posed
by ionising radiation. An indication of the range of concern may be discerned
from the variety of submissions in which these matters were raised. Apart
from submissions from government agencies and mining companies, see, for
example, Peter Milton (S 9, 4); Gavin Mudd (S 34); Frank Miller (S 35,
5); Michael Moore (S 36); Friends of the Earth Sydney (S 40, Part 2, 71-82);
Social Action Office, Conference of Leaders of Religious Institutes, Queensland
(S 55, 6); Peter Jones (S 66); Australian Nuclear Association (S 71, Part
4); Greenpeace (S 73, Part B); Roger Alsop (S 75, 2); Women Opposed to
Uranium Mining (S 76, 3-4); Women's International League for Peace and
Freedom (S 77, 6); Medical Association for Prevention of War (Australia)
(S 79, 9-10); Uniting Church Social Responsibility and Justice Committee
(S 83, 15-8); Movement Against Uranium Mining (ACT) (S 89, 5); and Conservation
Council of South Australia/Friends of the Earth Nouveau (S 92, 22-8).
Much analysis of radiation matters pivots on a proposition attributed
to the National Health and Medical Research Council that "[t]here
is no safe level of exposure to ionising radiation" (Australian Conservation
Foundation, S 81, 13). (Subsequently, the ACF informed the Committee that
attribution of this statement to an NH&RMC publication was a "mistake"
and that the NH&RMC had in fact said that "there is a small risk
even at very low doses".)
Dr Keith Lokan, Director, Australian Radiation Laboratory, explained
the proposition thus:
We would share the opinion of ICRP and the international agencies
that that [proposition] is correct. It is an assumption, supported by
the theories of radiation biologists, that one would not expect there
to be a threshold, and that the consequences of exposure will increase
with increasing exposure. It probably is not linear - that is, if you
decrease a given dose to half that dose, it is likely at low doses that
the future negative impacts would decrease by more than a factor of
two. But, yes, it is true that conceptually there is no "safe dose."
(11 February 1997, 1073)
In its submission the South Australian Government put the view that such
an interpretation of "safe" was not consistent with usual community
standards in assessing the risks of everyday activities:
It is frequently stated that "there is no safe level of
radiation exposure". This is only true if "safe" is defined
as "absolutely no risk at all". Such a statement is analogous
to the statement "there is no safe speed in a motor car".
If "safe" is taken to have its normal meaning that the level
of risk is so low that it is acceptable in the particular circumstances,
then "safe" levels of radiation exposure can be defined and
an appropriate dose limitation system can be applied. (S 109, 4.2.1,
16)
As has been reported earlier, the occupational dose limit has been reduced
to 20 milliSieverts (mSv) per year averaged over a period of five consecutive
years with a maximum of 50 mSv in any one year. Both Australian mines,
Ranger and the Olympic Dam Operation, are already within the new limit.
As the Australian Radiation Laboratory informed the Committee:
For both mines, the annual radiation doses to workers are well
below the recommended 50mSv of the Nuclear Codes Mining Code and about
one third of the 20 mSv limit recommended by the NHMRC and the NOHSC
in 1995. (S 80, 2)
A major reservation about the latest limits is that the trend has been
consistently downwards. As described by the Australian Conservation Foundation,
"[i]n 1950 the dose limit was reduced from 300 to 150 milliSv per
annum. It was reduced again, in 1956, to 50 milliSv. In 1977 the ICRP
reaffirmed the 50 milliSv limit. In 1985 the recommended public dose-limit
was reduced from five to one milliSv per annum" (S 81, 13, citing
Les Dalton, Radiation Exposures, 1991, 205).
A similar observation is made by the Conservation Council of South Australia/Friends
of the Earth Nouveau:
The recommended allowable exposure to ionising radiation has
been steadily decreasing from the earliest days of radiological protection.
There has not been a single case where the allowable dose has been increased.
As our knowledge of the effects of ionising radiation increases so the
risks associated with it have been found to be higher and higher. There
is an irrefutable trend in the assessed risk yet the NH & MRC and
other groups whose brief it is to protect people from ionising radiation
have not taken this into account. (S 92, 23)
The NH & MRC explain the most recent approach thus:
Risks arising from exposure to radiation should be kept
in perspective with other risks, so that society's resources are not
inappropriately expended in attempting to contain one particular form
of risk while providing too little protection from others. The Recommendations
incorporate a system of radiation protection which, if implemented properly,
should ensure that risks arising from exposure to radiation remain a
minor component of the spectrum of risks to which all people are exposed.
(NHMRC, Recommendations for limiting exposure to ionizing radiation
(1995) (Guidance note [NOHSC: 3022 (1955)], Radiation Health Series
No 39, r-1)
The matter of how conclusive the most recent limits will prove to be
was covered during the Committee's public hearings.
Dr Lokan, Director of the Australian Radiation Laboratory, explained
that:
. . . a careful and thorough re-evaluation of the radiation exposures
indicated that they [the former limits] had been overestimated by about
a factor of two. In addition, with the addition of further years of
medical data as the exposed population aged, the emerging number of
cancers exceeded earlier projections by about 50 per cent. (11 February
1997, 1071)
As a consequence, Dr Lokan concluded:
My opinion would be that they [the dose limits] will not drop
further. (11 February 1997, 1073)
Officials from the South Australian Health Commission laid emphasis on
the advance in knowledge upon which the 1991 values are based:
While our knowledge will obviously increase in the future, we
already have a reasonably good knowledge of radiation effects. A lot
of our knowledge depends on the study of the atomic bomb survivors in
Japan. Until those who were exposed in that population have all died,
we will not have the final information from that population. However,
I believe we are now getting close to a very good estimate from that
population, so I do not anticipate that there will be such very large
changes in the future.
(Mrs J Fitch, Director, Radiation Protection Branch, South Australian
Health Commission, 3 March 1997, 1726)
Mrs Fitch's observation was amplified by Dr Crouch, Senior Scientist,
Radiation Protection Branch, South Australian Health Commission:
. . . the thing that is driving this discussion is the 50-millisievert
limit which was set back in the 1950s or 1960s . . . [T]hat was not
much more than an inspired guess because, at that stage, there was very
little data from the Hiroshima and Nagasaki victims. So it is not at
all surprising that now, when people have had an opportunity to follow
them for 30 or 40 years after their exposure, the results are different.
(3 March 1997, 1727)
Several submissions were very critical of the time which elapsed between
the promulgation of the ICRP value in 1991 and eventual adoption in Australia
nearly half a decade later. According to Greenpeace, ". . . Australian
regulators have not responded in a timely or proper fashion" (S 73,
Part B, 2). The Medical Association for Prevention of War (Australia)
told the Committee that "[i]t is appalling to see radiation authorities
drag their feet on these regulations" (S 79, 10). For the Conservation
Council of South Australia/Friends of the Earth Nouveau the delinquency
was even greater:
The recommendations in the document were based on 1991 International
Committee on Radiological Protection (ICRP) recommendations, which followed
the 1989 US recommendations (BEIR V report), which followed the 1987
UK (NRPB) guidelines, which followed general acceptance of the assessment
of data from Hiroshima survivors which was known in 1981. It took the
expert NH&MRC Committee 14 years to get to the stage of making
recommendations.
This time lag is unacceptable and the delay can be attributed
at least partly to the nuclear industry who challenged the analysis
of the Hiroshima data and who have a large influence on committees such
as ICRP. (S 92, 22-3)
Mr Tim Ferrari, National Industrial Coordinator, Australian Liquor, Hospitality
and Miscellaneous Workers Union, was among those concerned by the delay:
I for the life of me cannot work out why there is such a problem
with ICRP 60 and why there has been since 1990. Those who say that people
have dragged their heels on ICRP 60 are correct. I am one person who
can say from my experience that people have wanted to drag their heels
on ICRP 60 and I cannot for the life of me think of any other reason
than Jabiluka. I think it can be worked out but it is going to cost
some money. If that is the problem, let people say so. (11 February
1997, 1404)
Dr Keith Lokan, Director, Australian Radiation Laboratory, explained
the process of adopting the ICRP values thus:
You need to understand that in our federation processes like
this, the development of new standards, can only proceed at a pace in
which they can be developed in a consensual way by all the players.
In this case, we produced a first draft document after the publication
by ICRP of its recommendations. We circulated that draft amongst all
of the afficionados. We went through seven drafts at various times exposing
it to interested parties and, ultimately, issuing it for public comment
in year four.
By the time we received the public comment, absorbed the public
comment, changed it accordingly and took it back to the Radiation Health
Committee, we had covered 4 1/2 years. Then it took another half a year
for it to go through the formal processes of adoption by the Occupational
Health and Safety Commission and the National Health and Medical Research
Council.
If not the first, we are among the first countries in the world to have
adopted the new recommendations. (11 February 1997, 1074)
Dr Lokan added that "[m]ost countries now are contemplating the
adoption of new standards, and more than likely many will take advantage
of the basic safety standards produced jointly by the International Atomic
Energy Agency, International Labor Organisation, World Health Organisation
and Food and Agriculture Organisation because they are tailor-made for
adoption as regulatory instruments." (11 February 1997, 1074)
The Committee does not regard delays of several years as acceptable.
The relevant authorities need to ensure that the processes are streamlined
and operate much more promptly in future. This may be achieved by provisional
promulgation of new standards in advance of confirmation following consultation.
Mr Ferrari was also critical of the variations proposed to ICRP which
effectively use a 10-year rather than a 5-year averaging period (11 February
1997, 1404).
Dr Lokan explained these changes:
The points of difference between our recommendations and ICRP
are: firstly, a more realistic recommendation regarding exposure of
the foetus, once a woman employee notifies her employer that she is
pregnant. Rather than a limit of two millisievert at the surface of
the abdomen, which ICRP proposed, we have used more general words saying
that the foetus should be afforded the same protection as members of
the public. This allows the regulator to assess the importance of internal
exposures from radioactive materials rather than only external exposure.
Secondly, Australian state and territory radiation protection
regulators wish to retain an element of flexibility whereby they could
consider exceptional circumstances and authorise temporary dose limits
different from and greater than a time averaged 20 millisievert per
year in order to correct the circumstance. Such circumstances - and
none are visualised at this time - would have to be approved for good
reason by the regulatory authority on a case by case basis. In all other
respects - including the longstanding justification, optimisation, dose
limitation philosophy and a commitment to ALARA - we have followed ICRP
closely and are in close accord also with the basic safety standards.
(11 February 1997, 1072)
Parenthetically it should be noted that not all informed observers endorse
the 20 mSv per year value averaged over five years without qualification.
Mr R M Fry (then the Supervising Scientist) and Mr M W Carter stated in
a paper delivered at an international conference in 1992 that:
The new occupational effective dose limit recommended in ICRP
Publication 60 (ICRP 1991) is 20 mSv per year averaged over defined
periods of 5 years, with the further provision that the effective dose
should not exceed 50 mSv in any single year. Some underground uranium
mines may find difficulty in complying with this limit. No country is
likely to forego underground uranium mining because of an inability
to strictly comply with the new limit if it is considered essential
in the national interest. For any departure from strict compliance to
be acceptable it must not lead to increased risks to miners. This paper
argues that the new ICRP limit, as formulated, is more prescriptive
than it need be on strict radiobiological risk grounds. Provided the
rate of radiation exposure is limited to avoid deterministic effects,
the lifetime risk is largely determined by the accumulated dose, not
the rate of dose accumulation. Whilst limiting average yearly exposure
to 20 mSv has regulatory convenience, it is arbitrary and there may
be industries in which occupational risk can be equally well controlled
through a lifetime or career dose limit. It is suggested here that underground
uranium mining may be regulated by setting an occupational lifetime
effective dose limit, which may be accumulated at rates faster than
20 mSv per year. A career limit for underground uranium mining, which
could, using a dose constraint, be set somewhat below the 940 mSv implied
by the ICRP recommendations, and a continuing strong emphasis on ALARA,
would ensure that miners are at least as well protected as they would
be by strict compliance with ICRP 60. Indeed, if the effect of a career
dose limit were to shorten the number of years uranium miners spend
underground, this would have the benefit of reducing their exposure
to the generally much higher conventional risks associated with underground
mining. (Abstract. Text attached to S 82)
The Select Committee is not a scientific body and it is not equipped
to enter a view on the scientific matters raised by the radiation question.
On this basis it has reached the following conclusions.
First, the scientific question is not yet settled. As one witness remarked,
"[t]he field is by no means mature" (Dr Philip Jennings, 20
January 1997, 949). The Committee believes that Australian health authorities
should continue to assemble and test data to ensure that any stipulated
dose level meets the claims made for it. This accords with a theme which
has occurred earlier in this report, namely the continuing importance
of research.
Secondly, it is also a field where ultimately individuals must make decisions
for themselves and their families. The Committee recommends that responsible
government health authorities together with mining companies and unions
with coverage should ensure that employees are fully briefed on radiation
and related hazards, personally, in some plain English documentation and
perhaps also by video.
The cost of such briefing should be met by the respective mining companies.
This proposal is not advanced as a criticism of past or present performance.
All the evidence available indicates that these have been satisfactory.
But it is not sufficient in a field which remains so open and where individuals
themselves are entitled to provision of full information as a basis for
arriving at a personal decision.
The Committee, however, considers that the present range of practices,
especially as currently demonstrated at Ranger, should be regarded as
minimum standards. Annual medical checks of employees exposed to radiation
should continue. Individuals should receive a post-examination report
in plain English.
Any new mines which open should adopt these practices as a matter of
routine.
Thirdly, in investigations about the various levels of radiation, the
Committee has often been told that the working rule, whatever may be legally
a maximum permissible limit, is ALARA - as low as reasonably achievable.
Both mining companies and regulatory authorities should actively continue
their pursuit of the ALARA principle and report on the extent to which
they succeed in operating well below prescribed levels.
There is also the matter of a national register of people occupationally
exposed to ionising radiation in employment. Called the National Radiation
Dose Register (NRDR), it is now being established by the Australian Radiation
Laboratory following a forum organised in 1990 by the National Occupational
Health and Safety Commission. The NRDR is a national database of the personal
radiation dose records of all Australians who have been occupationally
exposed to ionising radiation.
The NRDR is described by ARL:
The P[ersonal] R[adiation] M[onitoring] S[ervice] at ARL can
provide to the NRDR records detailing the external radiation exposure
to all workers in Australian uranium mines. Records of internal radiation
dose, from the inhalation and ingestion of radioactivity, are held by
State health authorities and the employers. Information and advice on
the available internal dose records for uranium miners is now being
collected by ARL and the NRDR has also approached the uranium mining
companies directly for information on worker exposure. With the establishment
of the NRDR it will be possible for a worker to obtain from a single
source a complete history of radiation exposure throughout the worker's
lifetime. It will also have benefits to regulators and users of radiation
in the assessment of the effects of changes in practice on occupational
exposure and will provide a useful set of data for any epidemiological
studies of the effects of radiation exposure. It is expected that the
database, including the external radiation dose records for the uranium
mining workers, should be in place by late 1996. (S 80, 5)
Notwithstanding action to establish the Register several organisations
advocated such a move in submissions to the Committee.
The Australian Conservation Foundation recommended that a national register
of all uranium mine and mill workers be established (S 81, 13). Women
Opposed to Uranium Mining recommended that "a national register for
all radiation workers, not only those employed in mining and milling,
should be established and all efforts should be made to track past radiation
workers so that epidemiological studies can be undertaken" (S 76,
4). The Medical Association for Prevention of War (Australia) expressed
its concern "about the fact that so far Australia has no national
system to record the exposure of uranium miners to radioactivity"
(S 79, 9).
The Australian Liquor, Hospitality and Miscellaneous Workers Union submitted
that:
. . . the uranium industry in Australia has not adequately or
responsibly participated in bringing forward comprehensive epidemiological
data for each exposed worker in current mining operations to assist
the world wide need for such information. Recording exposure levels
is important but unless all lifetime factors are also recorded as possible
confounding factors then there can never be conclusive results confirming
either high or low responsibility levels relating to fatality levels.
Similarly the industry has not given support to maintaining a
proper register of uranium workers both present and past, with regular
contact maintained with workers who have left the industry or who are
now working in other radiation exposed industries, eg mineral sands
extraction and processing.
Fry and Carter also state:
"an adequate system of cumulative dose accounting and its
strict surveillance for all workers within the industry, and a national
mechanism to ensure transfer of health and dose records between employers
would be required . . . " (S 82, 3)
There are, nevertheless, reservations about a national register. Mr Tim
Harrington, a member of the Environment Committee, South Australian Chamber
of Mines and Energy, considered that a national register could have two
uses. The first is simply the matter of keeping records of individuals
especially if they move from jurisdiction to jurisdiction. At present,
Mr Harrington said, ". . . it is up to the receiving state to obtain
the radiation records from the state or territory where the person was
before. That mechanism actually does work. It may not be as reliable as
a national register; therefore a national register has some merit."
(24 January 1997, 1046)
But, he continued, discussions for a national register took place in
"the context of a permanent repository of information for epidemiological
follow-up."
It is extremely unlikely - and some research was published quite
a number of years ago - that any future epidemiological study will find
concrete evidence of the results of exposure at the sort of radiation
doses that people in the mining industry are commonly exposed to. It
is a statistical fact that it is going to be extremely difficult and
probably unlikely . . . [T]here are people who think that those records
will supply concrete evidence of deleterious effects. I do not think,
on a statistical basis, that that body of evidence will show that. (24
January 1997, 1046-7)
Relevant to this question of a national register is a matter Dr Leigh
raised. He drew attention to differences in methods used by the two mines,
Ranger, an open cut mine, and the Olympic Dam Operation, an underground
mine, in measuring radiation exposures. Dr Leigh expressed a view that
there should be greater consistency in methods used by Ranger, Olympic
Dam Operation and any new mines so that there is "standardised confounder
data which is essential to any future epidemiological study, ie data on
other exposures (eg smoking, asbestos, chemical) which can cause cancer
or lung disease which may distort any epidemiological attempt to relate
radiation exposure to future cancers or other disease" (J Leigh,
35-6).
The Committee, whilst having regard to various reservations about the
statistical feasibility of epidemiological studies in Australia, agrees
that Dr Leigh's recommendation should be seriously considered.
Indeed, the Committee recommends that the ARL ensure that a uniform
method of measuring, calculating and recording dose limits is adopted
and applied in all mines. Public concern about radiation is such that
it is not sufficient for mining companies alone to determine how they
record exposure to radiation. The purpose of a national register is to
find consistency.
The Committee is not satisfied that the matter of career dosage has
been examined sufficiently thoroughly by scientific and medical authorities.
It is persuaded that the concern about this longer-term aspect of health
in the uranium mining and milling industries needs a more coherent response
than, as far as the Committee knows, has been yet given. Among the matters
to be addressed are the method of determining the career dose limit, and
the industry's own response.
It believes that this is a topic on which the ARL could take the lead
in consultation with mining companies and unions.
Health authorities should examine a means of compensation for employees
who exceed a career dose limit (when determined) prior to retirement age.
When the Committee was finalising its report its attention was alerted
to a paper by Professor Wolfgang Kohnlein of Munster, Germany and Rudi
H. Nussbaum of Oregon, United States. They summarise their perspective
thus:
. . . for decades radiation researchers have focused their attention
somewhat myopically on delayed cancer and genetic effects among A-bomb
survivors - a highly selected group of individuals - and on much animal
and radio-biological research at very high doses. Specific low-dose
or low dose-rate studies of populations or human cells, that suggested
that ionizing radiation might actually have an increased rather than
a reduced biological effectiveness at low doses, have either
been rejected outright, or ignored in reviews of radiation health effects.
Only very recently have there been persistent suggestions in the literature
that such unexpected effects which clash with firmly held beliefs among
a majority of radiation experts, might involve hitherto unknown and
rapidly saturating complex radio-biophysical or radiobiochemical mechanisms
at very low doses, very different from the well-known mutational effects,
proportional to dose, . . . ("Reduced Radio-Biological Effectiveness
at Low-Rate, Low-Dose Exposures [DREF] : An Unwarranted Conjecture",
n.d., 9-10).
The Committee, in the short time available, received brief comment on
the Kohnlein/Nussbaum view from Mr P.A. Burns of the Australian Radiation
Laboratory:
In their paper, Dr Kohnlein and Dr Nussbaum claim that the risk of
developing a fatal cancer is greater than that predicted in ICRP 60.
In ICRP 60 this risk is estimated at 5% per Sievert for the general
population whereas in their paper this risk is estimated to be 25% .
. . Whilst there is some uncertainty regarding these risks estimates
it is considered unlikely that they could be wrong by a factor of five.
If the risks were as high as suggested then nearly 30% of all cancers
in Australia would be attributable to background radiation and it should
be possible to observe variations of cancer rates with background radiation.
Such variations cannot be observed even with large variations of background
radiation, which can vary by a factor of ten around the world.
Further analytical comment from the Australian Radiation Laboratory is
in Appendix 4.1.
|
