Whilst the HP riser was being pulled, the Assistant Rig Manager noticed that a 6.5 ton shackle did not have a retaining ring attached. As he was removing the shackle the floorman appeared on the drill floor with the missing retaining ring stating that it had fallen and struck his left shoulder (Fig.1). No injury was sustained. The weight of the retaining ring was checked and found to be 122 grams (1.25 Lbs). Height of the fall was 16 metres (50 Ft). The lifting arrangement for the HP riser formed part of the newly certified lifting equipment. The lifting equipment had been examined and accepted 4 weeks previously. Corrosion of the break indicated that the ring had been broken for some time before this incident.