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Wednesday, 30 November 1983
Page: 3115

Question No. 386


Dr Everingham asked the Minister for Health, upon notice, on 24 August 1983:

(1) What is the estimated likelihood, at least in terms of 'more likely than not' or the opposite, of the following occurrences in the event of a one megaton nuclear explosion 2,000 feet over (a) Brisbane's business centre and (b) Amberley air base: (i) destruction of half the buildings within 20 kilometres within 60 seconds, (ii) destruction of all public hospitals within 10 kilometres , (iii) a fire storm and major fires for more than two days and nights destroying half the remaining undamaged or repairable damaged buildings within 32 kilometres, (iv) death within one minute of half the population within 32 kilometres (v) death between one minute and 48 hours with severe pain, or severe vomiting and diarrhoea, or weakness from loss of blood, or some combination of these, of half the survivors of the first minute within 40 kilometres, (vi) premature death between 48 hours and 25 years from similar causes, their complications or malignant disease of half the survivors of the first 48 hours within an elliptical area 120 kilometres by 16 kilometres extending mainly in the most common direction of wind travel from the target assuming a wind speed in that direction of 15 kilometres/h for 12 hours, (vii) loss of traditional food supply, water, electricity, communications, road, rail, air and sea transport for 48 hours for half of the survivors within 48 kilometres, (viii) infectious epidemic deaths within one month within 48 kilometres and (ix) 9 out of 10 health workers casualties for 48 hours within 48 kilometres.

(2) When does he expect to have the report being prepared for the World Health Organisation on nuclear war.


Dr Blewett —The answer to the honourable member's question is as follows:

(1) The following responses to the nine questions are based on information given in the United Kingdom Government publication 'Nuclear Weapons', which is a manual for civil defence in nuclear attack. As requested, the situation examined is the explosion of a one megaton nuclear weapon at 2,000 feet, but no distinction is attempted between an explosion over Brisbane's business centre and one over Amberley air base because to do so would entail an extensive and separate study.

(i) It is not likely that half the buildings within 20 kilometres would be destroyed within 60 seconds, but many would be destroyed and others could become irreparably damaged. For example, the limiting distance for severe to moderate damage to houses by blast is given as 9 kilometres, with light damage extending to 15 kilometres; whereas, the induction of fires by thermal radiation could extend as far as 15 kilometres, for very clear atmospheric conditions.

(ii) It is not likely that all public hospitals within 10 kilometres would be destroyed, but many would be severely damaged by blast and all would be subjected, to some extent, to fire.

(iii) It is not likely that a fire storm would occur, nor a catastrophic fire of the magnitude and extent suggested.

(iv) It is not likely that half the population within 32 kilometres would die within one minute. For example, the limiting distance for LD50 (lethal dose for 50 per cent of the population group exposed) for blast over-pressure is about 1 1/2 kilometres; for initial gamma radiation it is given as 3 kilometres; and for thermal radiation it would be somewhat greater.

(v) It is not likely that half the survivors of the first minute within 40 kilometres would die between one minute and 48 hours. For example, for exposure to the initial gamma radiation from the explosion, there would be no appreciable risk of sickness at distances beyond 3 kilometres. For thermal radiation, charring of the skin would occur out to 8 kilometres for unimpeded exposure in a clear atmosphere, but even modest screening would give substantial protection; the limiting distances for blistering, and for reddening, of the skin are given as 10 kilometres and 14 kilometres, respectively, for exposure in the open in a clear atmosphere. Blast-induced injuries-due to drag forces from the blast wind, rather than the direct overpressure-would occur out to 10 kilometres or so; these injuries would result, for example, from being hurled bodily against an obstacle or impaled by a projectile.

(vi) It is not likely that half of the survivors of the first 48 hours within the close-in fallout field would die of malignant disease during the subsequent 25 years. For example, for the idealized conditions postulated in the question, calculation indicates that:

if the population stayed in the area for 48 hours after the explosion, but remained in the open throughout rather than sheltering in buildings, then all would approach or exceed LD50 for radiation exposure

if the population stayed in the area for 48 hours after the explosion, but took effective shelter in buildings throughout, then about 10 per cent would approach LD50 for radiation exposure but the remainder could walk out of the area after 48 hours incurring a total risk of about one in 100 of contracting fatal malignancy.

(vii) It is more likely than not that there would be loss of traditional food supply, water, electricity, communications, road, rail, air and sea transport for at least part of the area. Public utilities above ground would receive severe to moderate damage to distances of about 9 kilometres, but underground services would be little damaged outside the crater zone.

(viii) It is more likely than not that there would be an increase in incidence of infectious disease.

(ix) The fraction of health workers unable to resume their duties after the explosion would depend to a large extent on injuries incurred during blast damage to the major hospitals and the extent of their inclusion in the close-in fallout field.

(2) I understand that the report referred to was completed some months ago by the WHO committee of experts and is now with the publisher.