Luminous Indicator Contains Strontium 90

Press, Volume XCV, Issue 28314, 27 June 1957, Page 7

Luminous Indicator Contains Strontium 90

The police had so far not been informed of any persons finding small indicators which contained a luminous substance activated by strontium 90, said Chief Inspector E. J. C. Hay. of the Christchurch police yesterday.

Such an indicator was found a few weeks ago in a rubbish tin outside a Sumner shop, and handed to the police The police obtained a report from the Dominion X-ray and Radium Laboratory that the object was dangerous if broken open or tampered with, because of the danger of ingesting or inhaling strontium 90. which collects in the bones and there gives off radiation. It is thought that the indicator found at Sumner was taken from a ship of the United States Antarctic Expedition which visited Lyttelton during the summer. The indicators, which glow in the dark, are screwed to cabin doors and the railings of companionways in American ships, to act as markers in the dark. They are not used in New Zealand or in New Zealand ships. Physicist’s Warning

Mr J. F. McCahon, a physicist at the Dominion X-ray and Radium Laboratory in Christchurch, said yesterday that the object found was not i eally a reflector. A reflector merely reflected light from some source This object gave out light from itself in complete darkness. it glowed just as did the luminous dial of a watch.

The indicator contained a substance called a phosphor which emitted light when exposed to beta rays from the small amount of strontium 90 contained within it.

The clear plastic covering on the front of the object was about half an inch thick, said Mr McCahon. This thickness was re quired to prevent the escape of the powerful beta radiat’on from the strontium 90. If it were broken and the substance containing the strontium 90 exposed, danger would result. If as much as a thirtieth part of the substance was ingested or inhaled, the person absorbing it was definitely likely to stifferfrom the effects produced by radioactive materia] in the bones Some of the effects produced were leukemia and bone tumours, he said.

If the whole of the substance was absorbed, it was quite possible that acute damage to the blood-forming mechanism would result. This could be fatal. Process of Luminosity The process of luminosity was similar to the luminosity of a watch with a luminous dial, which was activated by a minute amount of radium. The quantity of radium in a watch, however, was so small that it did not present any significant hazard to the wearer, said Mr McCahon.

“Where a large enough number of watch dials are handled, as in factories, they can be quite dangerous,” he said. Paint or any substance activated by strontium 90 was considerably more dangerous than paint activated by radium. Similar objects to the indicator found at Sumner were used during the war by American. troops in jungle warfare, he said. Each member of a jungle patrol would

wear an object on the back of his jacket and the glowing objects enabled men to follow one another in single file in pitch darkness. Any persons finding or being in possession of such luminous ’ndicators should hand them over to th? police, said Chief-Inspector Hay. Such persons could well note the warning “Radioactive poison inside . . Bury if damaged.” which was written on the indicator found, he said.