Alarm Condition II  Gas concentration between 10 - 49 ppm. Moderate danger to life. The siren in the "drilling area" will sound automatically when H2S concentration exceeds 15 ppm. A close watch will be kept on the H2S detectors after the initial alarm has tipped. When H2S is detected in quarters and/or concentration of H2S gas reaches 20 ppm outside, anywhere on the rig, the general "Gas Alert Signal" will be sounded. All quarters will be evacuated and non-working personnel will proceed to the "Gas Alert Stand-by Station" - "Safe Briefing Station" Drill crew and other essential personnel will commence to wear breathing apparatus and continue with their respective jobs - bearing in mind that the "Buddy System" must be used while wearing the breathing apparatus. The Barge Captain will call the supply boat (stand-by boat) and ask them to pick up his anchors and proceed to an upwind position to await further instruction. Radio communication shall be used to notify Shore Base and helicopters at this stage. Supervisors at the "Safe Briefing Area" will watch the windsocks and flags to keep track if wind direction. All personnel in contact with H2S will wear protective breathing apparatus. Alarm Condition II Immediately the presence of Hydrogen-sulphide at concentration of 20 ppm is suspected, as indicated by the H2S detector, all rig personnel will wear breathing apparatus. Derrick man and shaker hand will be informed immediately and instructed to wear their breathing apparatus. Call drilling superintendent and Company representative.  Check H2S concentration with Draeger gas detector at: Rig floor Shale shaker Mud pump room Cellar deck Start bug blower at standpipe manifold. Keep contact with mud logging unit and engine control center re H2S concentration. Transfer Possum belly tank into active system and leave dump valve open (overboard).  Open bottom valve (5") at poor boy degasser so that mud will be able to run from degasser into possum belly tank and overboard. We will not circulate H2S gas-cut mud, but dump all returns overboard. All bug blowers at mud pump room, shaker area and cellar deck to be started. Alarm Condition II Crane driver will Close all watertight doors on deck. Open all doors to cellar deck. Set warning signs, reading "Danger - Poisonous Gas" at forward and aft ladders to rig floor. Crane driver will set warning sign, reading "Danger - Poisonous Gas" at heliport facing so that the pilot will be able to see the sign. All non-essential personnel will proceed to the "safe briefing area". Crane driver will stay in contact with drilling superintendent by means of walkie-talkie Channel 13 for instructions  breathing equipment. As soon as this instruction is given, all essential personnel, i.e., all personnel outside the safe briefing area, will wear breathing apparatus. Crane driver will start all bug blowers on main deck and at shale shaker.