In the third accident involving Delhi Metro in the last 10 days,a labourer was killed after he was hit by a steel beam being lifted by a crane at its site in west Delhi on Wednesday as DMRC chief E Sreedharan put the blame on the contractor for the fatal mishap. The incident took place at around 5:45 am at Ashok Park work site in Punjabi Bagh when the labourer was hit by the beam which was being lifted by the crane. "The beam was being lifted for staging work at the station when the incident happened. The incident took place only because the chain of the crane used to lift the beam snapped," Sreedharan told reporters in New Delhi. The station is part of the under-construction Inderlok-Mundka line. The semi-skilled worker,identified as Vicky Singh (22),hailed from Uttar Pradesh. Singh was guiding the crane movement and prima facie,it appears that the beam hit him on the shoulder. He was rushed to the nearby Maharaja Agarsen Hospital where he succumbed to injuries. Sreedharan blamed the contractor IDEB-SUCG JV for the accident,saying the crane used by the contractor was new and the slings used were "not certified". "We have a very rigorous system of checking our lifting substances. In this case,the contractor got a new crane,a new operator and slings. Nobody checked it," he said,adding,the victim "should have also been little careful in guiding the beam."