Worker finds, tosses lost radioactive metal

A worker who picked up a piece of radioactive iridium-192 metal and kept it for more than three hours in Nanjing, Jiangsu province, on Wednesday has been transferred to Suzhou to receive treatment.

The worker, surnamed Wang, told police that he noticed the bracelet-shaped object when he was sweeping the floor of a construction company's welding workshop around 8 am.

He thought it was valuable, so he put it into his jacket pocket.

During his lunch break three hours later, Wang discarded the source into the yard of his house. After learning that a radioactive substance had been lost at the company and that the police had begun a large-scale search operation, he then wrapped the metallic object in a blue plastic bag and threw it into some bush near his home.

"The mortality rate is high if people are exposed to a large amount of radiation," said Tang Shuangling, director of the radiation prevention and environmental protection department under Nanjing University of Science and Technology.

"The main effect of radiation is on the immune system. Patients often get sick, even if they survive."

The environment in which Wang discarded the radioactive metal - including the earth, water and air - has been examined and found to be safe, according to Lu Jigen, head of the nuclear and radiation safety supervision management bureau of Jiangsu province.

"The source doesn't harm the human body if people keep a distance of tens of meters from it," Lu said.

Iridium-192, a silvery-white transition metal, is a radioisotope of iridium with a half-life of 73.8 days. It is often sealed by welding into a stainless steel case for various uses.

The substance is widely used in brachytherapy, a technique for treating cancer by inserting radioactive material into the body near a tumor. It is also used in industrial radiography to check for flaws in metal castings and welds. It can cause cell damage in people.

On Wednesday morning, due to an equipment failure, four workers with Tianjin Hongdi Engineering Inspection Development Co lost the radioactive disk during a monitoring operation at a construction company under Sinopec, a Chinese oil refiner.

Police detained the four on Saturday. They had violated regulations, including storage rules, police said.

Iridium-192 has been involved in a number of radiological accidents both in China and elsewhere in the world.

News of a notice issued by the provincial health bureau to local hospitals advising them to be alert for symptoms of radiation sickness began to spread on the Internet on Friday evening, but the news was not officially released by environmental authorities until noon on Saturday.

Wang Yuhua, director of the provincial environmental department, said the authorities needed to verify information, including where the radioactive source might have been discarded, before releasing information to the public.

"Unnecessary and large-scale panic among the public should be avoided because such information is highly sensitive," Wang said.

Contact the writers at cangwei@chinadaily.com.cn and songwenwei@chinadaily.com.cn