Three contractors at a site where two workers died in a caisson accident two days before Christmas are being prosecuted for breaching safety regulations. Paul Y Construction, in charge of the Smithfield Road flyover extension project, sub-contractors Lee Ping and Wong Fook-leung each face two summonses from the Labour Department. Paul Y allegedly failed to ensure the safety of a working platform in the 37-metre hand-dug caisson and to test for dangerous fumes and oxygen content. Lee and Wong were accused of failing to provide a safe system or give information, instruction, training and supervision for bar-fixing work in the caisson. Yesterday, after an inquest into the death of the workers, Vincent To, representing the three, said they had been ordered to appear in Western Court on September 17. The case was adjourned on July 5 pending conclusion of the inquest. Coroner John Saunders heard yesterday that Lee Cheung-kwan, 36, and Vietnamese Vu Trong Duong, 18, fell 30 metres when falling steel rods hit them as they worked on a wooden platform six metres from the top of the caisson on December 23. The bodies were recovered on Christmas Day after a 53-hour rescue effort. The caisson, with a diameter of 1.8 metres, was being filled with concrete at the time, the inquest heard. Principal fireman Lam Kam-pui told of how he discovered the two dead workers. 'The two looked as if they were embracing each other face-to-face,' Mr Lam said. 'Some of the metal bars had penetrated their bodies.' Forensic examination showed Lee died from lung injuries with multiple fracture of ribs. Vu, also known as Le Ah Duong, died from spinal injuries. The Vietnamese, from the Whitehead detention centre, was using a false refugee card to work. A video, taken by inspector Chow Wing-tat on January 4 inside the caisson, was shown. Mr Chow said he had found polystyrene foam protective boards missing 19 metres into the caisson. The inquest continues today.