Shenzhen X-ray scanners in subway radiation scare

Nearly 300 X-ray luggage scanners installed at Shenzhen underground stations in June have violated the mainland's radiation regulations and could increase cancer risks for children and pregnant women sensitive to radiation, local media reported yesterday.

The 286 scanning machines were installed at a cost of 120 million yuan (HK$146 million) to shore up security ahead of the University Games hosted by Shenzhen in August. They have been used daily by millions of Shenzhen and Hong Kong residents.

However, the devices had yet to obtain legally required radiation safety permits from the provincial environmental protection authorities or undergo any environmental impact assessment, The Southern Metropolis News reported.The paper quoted the Shenzhen Habitat Environment Committee, the agency in charge of managing the city's living environment, as saying the scanners were unlawful.

The committee said it was not able yesterday to comment on the scanner issue.

An official from the committee told The Southern Metropolis News that the amount of radiation delivered by the scanners was close to the safety standards set out by the national environmental protection watchdog.

That meant there was no need to apply for the usual radiation safety permits.

However, a test jointly conducted by the committee and the newspaper found the radiation readings at the entrances and exits to two Shenzhen subway stations, Shangmeilin and Jingtian, surpassed one microsievert per hour - a level that does require a radiation safety permit.

Dr Ivan Wong Yiu-chung, a council member of the Hong Kong College of Radiologists, said radiation from the scanners has been underestimated, but was always a concern, especially for children and pregnant women as they were more sensitive to radiation exposure that could increase the risk of cancer.

'Radiation in industrial devices used for security checks is packed in a self-contained cabinet where leakage has been reduced to extremely low levels, if not undetectable,' Wong said. 'But this varies for individual machines, depending on how frequently they are being used and maintained.'

He added that it should not be a major concern if the machines had passed inspection. In the United States, the Food and Drug Administration requires X-ray luggage scanning devices to be properly calibrated and maintained.