A Shenzhen hospital offering free surgery to 100 victims of a toxic gel used in breast enlargements has falsely claimed its techniques for removing the gel are patented, a patent official said yesterday. The gel, known as PAAG, was commonly used on the mainland, particularly in breast enlargements, until the State Food and Drug Administration banned it last month in response to concerns first raised by Hong Kong's Consumer Council about its safety. The council warned the gel could cause cancer and said six women had had one or both breasts removed after PAAG injections went wrong. The Shenzhen Peng Ai Medical Beauty Hospital, a subsidiary of the Peng Cheng Hospital Group, has been advertising free surgery to remove the gel using 'patented PAAG removal devices'. But an official at the State Intellectual Property Office yesterday said no such patents had been awarded, and suggested the hospital 'was conducting false advertising based on false information'. 'It has not acquired any approval or certificate for its new devices,' the official, from the office's inquiry department, said. The hospital claimed it could remove at least 90 per cent of the gel injected and immediately replace it with safe silicon implants. But leading surgeons including Qiao Qun and Qi Keming have said that once injected, the gel cannot be fully removed. An estimated 300,000 people have been injected with the hydrophilic polyacrylamide gel, and many women have expressed interest in having it removed. The South China Morning Post visited Peng Ai Hospital on Tuesday with three women keen to have the gel removed, including Ms Deng, a 21-year-old Shenzhen woman who said she had a breast augmentation in April 2005 but had since experienced severe pain. 'The doctor touched my breast and told me the gel had moved up. He promised to remove 99.9 per cent of the gel,' she said. 'Immediately, he and the nurse convinced me to have the silicon implants. 'He also said the [free] promotion ended on May 30 and covered just 100 victims, and that 90 had already registered for it. If I wanted to do it, I had to register quickly. 'He said silicon augmentation usually cost 30,000 yuan, but during the promotion I could get free removal surgery and an augmentation for 10,000 yuan.' Hospital staff could not explain why it had been promoting the procedures as being patented.