Airport officials emphasised that there was no need for panic. The incident did not affect airport operations, they said. The passenger terminals of the airport are about 2 km away from the cargo area.
Two workers who handled the consignment and complained of irritation in the eyes were taken to hospital for a preliminary check and are back at work. An airport spokesman said a preliminary assessment found the material, Sodium Iodide Liquid Class 7 for medicinal use, "of low radio activity."
"The radioactive leak was very very small. There is nothing to panic about and there is no effect on the passenger area," said National Disaster Response Force or NDRF chief OP Singh, whose teams sanitise the cargo hold and cordoned it. Atomic energy experts too were at the spot to remove the radioactive material.
Officials said four of a consignment of 10 cartons of the sodium iodide meant for a private hospital had leaked. It is used in so-called nuclear medicine for the treatment of hyperthyroidism and thyroid cancers. It emits radiation and must be handled with care to minimise inadvertent exposure to health workers and patients, an official at the Atomic Energy Regulatory Board (AERB) told Reuters.
Turkish Airlines said in statement, "The cargo package containing medical material and carried by Turkish Airlines' TK716 Istanbul - Delhi flight has been examined by the official authorities in Delhi on suspicion of radioactive leak due to the wetness seen on the mentioned package."
It said radiological surveys on board the aircraft when it landed back in Istanbul found "no evidence."
In 2010, a scrapyard worker in Delhi died from radiation poisoning and seven others were injured, raising concerns over the handling of radioactive material in the country.
Environmental group Toxic Links estimates that India produces five million tonnes of hazardous industrial waste every year and imports 5,000 tonnes of scrap metal every day.
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