safety measures were in place to prevent balloons from breaking loose. Despite this, two balloons broke free during a squall on 22 July 1959. One was subsequently recovered but the other was not. A board of inquiry was held, but an even more embarrassing incident occurred on the night of 23/24 September 1960, when seven of the eight balloons being readied for experiments broke free of their moorings during a thunderstorm. Five were recovered on the range on 27 September, but two were lost and drifted further afield, one being recovered near Cobar in New South Wales on 24 September and the other around Hungerford in New South Wales, which was not located until 1 October. Titterton wrote a critical letter to the AWRE. It was clear that the procedures to prevent balloon escapes had been inadequate and the self-destruction devices were unreliable. Fallout In the late 1950s, Hedley Marston's research into nuclear fallout from the Maralinga nuclear tests brought Marston into bitter conflict with the AWTSC, resulting in one of the more memorable feuds in Australian science. Marston was the head of the Division of Biology and General Nutrition at the CSIRO, and was commissioned by the AWTSC to study the concentrations of iodine-131 in the thyroids of sheep and cattle. A 1954 American report assessed that there was no public health danger, but the AWTSC wanted to be able to monitor the Australian situation. Surveys started before the tests at Maralinga commenced in order to establish a baseline. Marston's results indicated a rise in iodine-131 due to Operation Mosaic. It was not enough to pose a public health hazard—his results indicated that the concentration was about 1 per cent of the acceptable limit—but it did indicate that fallout was more widespread than first thought. He then attempted to extrapolate his results to strontium-90, but a valid assessment could not be made in this way, and was therefore no more than speculation. In 1961 the AWTSC published a study where the bones of deceased people (especially children) were burnt to ash and then measured for strontium-90. It did find an increase in strontium-90 in Australia, but it was a quarter of that recorded in the UK. Although fallout from the 1958 Operation Grapple thermonuclear tests was detectable in the UK, none was detected in Australia. Closure Maralinga was conceived as a testing ground where major tests could be conducted