Two construction workers who died in a caisson accident may have removed their safety belts just before the tragedy. Workers Lee Cheung-kwan, 36, and Vu Trong Duong, 18, were buried in a tangle of steel after the platform in the caisson where they were working collapsed on December 23. Yesterday Lee Ping, a sub-contractor at the construction site in Smithfield Road, told an inquest the pair were not wearing their safety belts, as was the regulation, when their bodies were recovered from the 37-metre caisson on Christmas Day. But Mr Lee said he had witnessed the two putting on the safety equipment before they entered the underground hole. Mr Lee, who has more than 15 years' on-site experience, faces two summonses from the Labour Department following the tragedy. He allegedly failed to provide training and a safe workplace for the two who died and is due to appear in Western Court on September 17 in separate proceedings. Mr Lee told the inquest he had given both men training. It took the form of lectures on how to use safety belts, helmets and other accessories. He had also asked Vu to make sure he had relevant experience. 'Vu told me he had worked elsewhere, including in a caisson, for a long time,' said Mr Lee. 'I then gave him one week to practise. When he was given a new task I would ask him to show me that he did know how to do the job.' The inquest heard that after the tragedy, two safety belts were taken from the caisson. They were tied to one safety rope instead of two as they usually were. But Mr Lee said he did not know why they were knotted in such a way. The inquest continues.