Maralinga revisited

by Peter Mac

Two weeks ago The Guardian ran a story about the Federal 
Government's controversial decision to change the clean-up method for the 
former Maralinga atomic test site.

As we reported, the site had become largely uninhabitable, due in part to 
radioactive waste dumped in pits, after the tests.

Several years ago the Australian and British Governments finally agreed to 
clean up the site. The proposed method, as agreed with the local Tjarutja 
people, was to seal the waste in a form of glass (vitrification) prior to 
reburial.

Although expensive, this method would have prevented dispersal of 
radioactive particles into the atmosphere or through the water table, thus 
providing a safe environment for return of the Tjarutja people.

However, following a mysterious explosion during vitrification, and after 
some waste turned out to be not as radioactive as previously thought, the 
Federal Government decided to halt vitrification and rebury the material in 
new pits below the level of the underlying limestone.

The disposal method was thus altered from the most effective and expensive 
to the least effective and least expensive.

The Government cited advice from the British Ministry of Defence and others 
that the explosion was most unlikely to have been caused by old buried 
explosives, and that there was no conclusive evidence as to its cause.

The Government thereby used the alleged "insoluble mystery" of the 
explosion's cause, and the presumed continuing danger to site workers, to 
terminate the program.

However, new information now makes clear that explosive materials, as well 
as contaminated soil from the tests, were dumped in the original pits, that 
these almost certainly caused the explosion, and that the Government was 
almost certainly aware of this.

Avon Hudson, a former leading aircraftsman in the Royal Australian Air 
Force who worked at the site in the 1950s, has stated that pressurised 
hydrogen cylinders and projectile heads for chemical explosives were buried 
with the contaminated soil after the tests.

Mr Hudson said he recently tried unsuccessfully to advise the responsible 
Federal Minister, Senator Nick Minchin, of this, and that he had never 
received a return call from him.

Regarding the pit for burial of the hydrogen cylinders, Mr Hudson noted 
that "This was a separate hole to where I had seen the box of explosives 
put ... there was a hole there, probably about 10 or 12 feet deep ... and 
there was a cylinder dumped there, ... about 7 feet long....

"If they had to get rid of anything, well it was just chucked into a pit. 
They didn't distinguish between a nuclear debris and say a barrel or a 
cylinder or any other debris. ... They didn't really separate those into 
categories, because nobody gave two hoots. They had one interest, and that 
was getting out of Maralinga ..."

The Government has also relied on advice from Britain that explosive 
residues would not have been likely to pose a continuing health hazard.

However, this advice is entirely speculative, and is contradicted by a 
letter from its Assistant Chief Scientific Adviser (Nuclear) to Senator 
Minchin. This stated that "It is clear that the team at Maralinga were very 
lucky not to have had any injuries. ... There can be no guarantees that 
there are not small amounts of explosive residues in the pits."

The presence of buried explosives was therefore almost certainly the cause 
of the clean-up explosion. (Munitions from World War I were still exploding 
60 years afterwards, in soil conditions far less stable than those at 
Maralinga.)

Moreover, the Government appears to have relied on very limited evidence 
arising from vitrification carried out to date in order to assess the 
extent of the contamination.

The Minister for Aboriginal Affairs, Senator Herron, stated recently that 
"On the basis of the previous melts, the percentage of plutonium was 
estimated to be less than 100 grams in 400 tonnes".

However, given the extreme toxicity of the material, it is entirely 
possible that this is still an unacceptably high level of contamination.

Moreover, it is most unlikely that the contamination was uniformly 
distributed within the buried material, comparatively little of which had 
been processed before the explosion occurred. This material can therefore 
hardly be regarded as representative of the level of contamination of the 
waste as a whole.

It is doubtful whether the bland assurances offered by the Government 
regarding the safety of the Maralinga site would be acceptable if the 
material was to be located in, say, Vaucluse or Toorak.. But then, perhaps 
the Government reasons that if second-rate treatment of the site was the 
order of the day for the Tjarutja people in the 1950s, it's good enough for 
a second attempt at cleaning up the site today.