H2S Exposure Code of Practice

Transcription

1 2013 H2S Exposure Code of Practice Chinook Drilling 4/15/2013

2 2 SUBJECT: HYDROGEN SULFIDE GAS - Responsibilities and Duties - H2S Wells Responsibilities and Duties All Personnel 1. Familiarize yourself with the procedures outlined in this book. Pay close attention during safety meetings and simulated emergency situation practice sessions. 2. Look out for your own safety first if an emergency occurs. 3. Then help anyone who is injured or overcome by toxic gases to a safe area. 4. Follow your supervisor s instructions explicitly. 5. The rig manager will assign someone to administer first aid to anyone unconscious or injured. 6. When operations approach the potentially hazardous period (well depth pay zone), any person who has not received training in the use of emergency equipment and in the procedure outlined in this book will be restricted to the safe briefing area unless accompanied by the rig manager or by a person designated by the rig manager. Drilling Rig Manager 1. Is responsible for strict adherence to these safety and emergency procedures by anyone on the drilling sites. 2. Will advise management when the procedures as specified here have been met; he will see that the procedures are observed at all times; he will advise management of any conditions specified here that are not followed. 3. Will keep the number of people on location to a minimum during hazardous operations. 4. Will notify management at least two weeks before safety equipment specified in these procedures is needed. 5. Will advise his key contact with the operator and each service company that all personnel assigned to the job site are required to have a physical examination for perforated ear drums and that no person having a perforated ear drum will be permitted at the job site when operations reach the potentially hazardous period. (Our medical director recommends that persons with perforated eardrums not be allowed to work around hydrogen sulphide because the perforations can provide a route to the lungs that cannot effectively be blocked with earplugs.) 6. Will advise all others entering the site during the Potentially Hazardous period of normal hazards and the extra hazard to those with perforated eardrums.

3 3 7. Will cooperate with the operator personnel for designating the safe briefing area. This area may change depending on wind direction and must be re-designated immediately upon wind direction change. 8. Will assess the situation when alarm sounds and issue work orders or, when conditions warrant, order all personnel to safe briefing area. 9. Will immediately notify or assign someone to notify the division office of an emergency situation. 10. Will enforce buddy system when assigning emergency duties during critical areas. No one will engage in emergency duties in critical areas without a buddy. 11. Will authorize evacuation of local residents if gas threatens their safety. The residents downwind of the location will be evacuated first. 12. Has full responsibility of the decision to ignite the well in the event that operator personnel are not present or they are incapacitated. The decision will be made only as a last resort and in a situation where it is clear that: a. human life and property are endangered b. There is no hope of controlling the blowout under the prevailing conditions of the well. c. Will direct corrective action to control flow of gas. d. Will designate an alternate for the safety representative if required. e. Will order driller to secure rig if time permits. 1. Drilling - Driller Will assume all responsibilities of operator personnel and rig manager in the absence or incapacity of both in an emergency situation. 2. Will secure rig in an emergency situation if time permits after putting on his gas mask. 4. Safety Company Representative Will provide training sessions for Chinook Drilling, personnel on the operation and care of safety equipment and review procedures outlined. 7. Will monitor the supply of required safety equipment and see that it is operational.

4 4 8. Will make himself available to assist the operator and service personnel in classes on the operation and care of safety equipment and in the reviewing of procedures outlined in this plan. 9. Will check safety equipment prior to spud in to ensure that it is stored in the proper places and protected against the elements. 10. Will provide assistance and advise management in an emergency situation as follows: a. Under alarm conditions, will test the area, determine the concentration of H2S and advise the rig manager on safety precautions to be taking to ensure safety of personnel. b. Under Hazardous Conditions, when authorized by operator personnel will: i. Clear the nonessential personnel out of the potential danger area. ii. Order all essential personnel to check their safety equipment for operating condition and see that it is in the proper location indicated on the rig superintendent s list. PERSONS WITHOUT SELF-CONTAINED BREATHING APPARATUS CANNOT WORK HAZARD AREAS. iii. Set up roadblocks and prevent entry of unauthorized people. iv. Increase gas-monitoring activities, including use by individuals of spot detectors. v. Evacuate local residents within the danger zone if gas threatens their safety. vi. Request help from local authorities to evacuate local residents and to control traffic into the threatened area Drilling Office Will provide a drill site location plan and an area map showing all occupied buildings within two miles together with a list, to the area map, showing occupants family names and number of people ordinarily in each building, and their telephone numbers.

5 5 5. Will communicate with the operator s office to determine drilling program and danger zones. 6. Will communicate with the operator s office regarding disposition of safety precautions and developing an emergency contingency plan. 7. Will communicate with Chinook Drilling, rig manager daily on progress and anticipated procedures. 8. Will provide assistance to rig manager as required regarding personnel, equipment and/or organization. SUBJECT: HYDROGEN SULFIDE GAS - Personnel Protective Equipment - H2S Wells The Hydrogen Sulphide H2S Detector, It s Use and Value All crewmembers shall be trained to use this simple and effective testing device rather than relying on the sense of smell. This instrument will give you an accurate reading in percent concentration of the gas present from.0025% or 25 PPM to.04% or 400 PPM. NOTE: The readings you take from time to time with this detector represent only the concentration of the gas at the location of the sampling line inlet at the time of test. Therefore, test frequently (every two or three stands if necessary) when gas is encountered and is clearly shown as a discoloration of the granules in the testing tube. PRINCIPAL OF OPERATION The H2S piston type detector consists of a detector tube, a moveable scale reading in the % ppm of gas. A piston pump creates a vacuum that draws the tested air through the tube to react with the white chemical granules and will darken them if H2S is present. HOW TO MAKE A TEST

6 6 Break both ends of the detector tube (where scored) using hole in bottom of frame near bulb. Insert the arrow end towards the cylinder. You are now ready for testing. While moving in area of crew s faces and general working area (and not held over pipe box); following the specific pulls of the tubs that are being used. Then you are ready to read the scale. NOTE 1: Whenever your reading shows.005% (50 PPM) start using blower fan to keep gas away from working area and have all in area stay on windward side of gas origin. Keep blowers going in all showings of gas. NOTE 2: Ensure your tarps and windbreakers are removed by now to keep from housing in gas on the rig floor. Self Contained Breathing Apparatus (SCBA) 1. Principles of the Operation of a Self-Contained Breathing Apparatus. (I.E. Scott Air Pak.) These units provide eye and respiratory protection and consist essentially of a full-face mask, corrugated rubber breathing tube, pressure demand regulator, air supply cylinder and harness. Both the self-contained models and extension hose models operate on a pressure demand principle whereby pure breathing air from and air supply flows to the face mask automatically and continuously creating a constant positive pressure in the face mask, providing air to the user as required as well as preventing contaminated air from entering the face mask accidentally. There are various types of varying capacities being used today. All employees shall be familiar with the units they will be using. 2. An adequate number of approved type self contained breathing apparatus must be on hand and in good operating condition. Each rig manager, crew

7 7 NOTE: member and company well attendant will have had previous instruction in the application and use of these units. Rig Manager will notify operator and service personnel ahead of time that we only have enough equipment to protect our own company personnel. Also, Rig Managers will be responsible for the training of crews in the use of this equipment. 3. Be sure masks are tested before using (i.e. check face mask, regulators, and all apparatus, parts and connections.) SUBJECT: HYDROGEN SULFIDE GAS - Preplanning for Drilling H2S Wells In high concentrations of hydrogen sulphide, death can result if proper precautions are not taken. The following points should be learned and discussed often by everyone involved at the well site. Hydrogen Sulphide Gas Characteristics of H2S 1. Extremely toxic (poisonous). 2. Heavier than air and colorless --- specific gravity of Has odor of rotten eggs (in small amounts). 4. Ignition temperature is (500 F, 260 C). It burns with a blue flame and produces sulphur dioxide (SO2) gas that is very irritating to eyes and lungs. The SO2 is less toxic than H2S but can cause serious injury. 5. H2S forms an explosive mixture with the air between 4.3% and 46% by volume. 6. H2S is soluble in water, but less soluble as the temperature increases. 7. H2S is almost as toxic as hydrogen cyanide and is between 5 and 6 times as toxic as carbon monoxide. 8. Produces irritation to eyes, throat and respiratory tract. The Principal Hazard is Poisoning by Inhalation

8 8 1. The sense of smell cannot be depended upon to detect H2S because exposure causes paralysis of the olfactory nerve. a. Sense of smell can be lost in two to fifteen minutes of exposure to low concentrations. b. Sense of smell can be lost in 60 seconds or less in higher concentrations. 2. Results of Inhalation a. Strangling may occur after a few seconds of exposure to high H2S concentrations. This produces such symptoms as panting, pallor, cramps, and paralysis of the pupil and loss of speech. This generally is followed by immediate loss of consciousness. b. Death can occur quickly from respiratory and cardiac (heart) paralysis. (One deep sniff of high concentration can cause instant death). c. Coughing, eye burning and pains, throat irritation and sleepiness comes from exposure to low concentrations. TREATMENT H2S acts so quickly that there is often no time to call a doctor before beginning to revive the victim. Follow the seven step response strategy. 1. Put on YOUR breathing apparatus. 2. Remove victim to fresh, pure air immediately. (Remember to protect yourself in rescue). 3. Keep victim warm and at rest. 4. If he/she is not breathing, begin applying artificial resuscitation at once. (Exercise care due to possible lung congestion.) Seconds count. 5. Don t wait to get a resuscitator. Let someone else get it if he/she is available. 6. When available and set up, use the resuscitator in place of mouth-to-mouth resuscitation. In acute poisoning, continuous use of oxygen is of great value. 7. Call a doctor or take the victim to a doctor as soon as possible. H2S TOXICITY TABLE PPM % CONCENTRATION NOTIFIER EXPOSURE/FIRST AID

9 9 1 PPM.0001 % (1/10,000 of 1%) Can smell 10 PPM.001% (1/1,000 of 1%) Can smell 8 hours exposure allowed ANY CONCENTRATION IN EXCESS OF 1 PPM REQUIRES PROTECTIVE EQUIPMENT 100 smell May sting eyes and Kills in 3 to 15 minutes.01% (1/100 of 1%) PPM throat 200 smell Stings eyes and Kills rapidly.02% (2/100 of 1%) PPM throat 500 PPM 700 PPM 1000 PPM.05% (5/100 of 1%).07% (7/100 of 1%) Lose sense of reasoning and balance Immediate loss of consciousness.10% (1/10 of 1%) Unconscious at once Respiratory paralysis in 2 to 15 minutes. Need prompt artificial resuscitation Breathing will stop and death result if not rescued promptly. Immediate artificial resuscitation required PERMANENT BRAIN DAMAGE MAY RESULT UNLESS RESCUED PROMPTLY Preplanning for Drilling Hydrogen Sulfide (H2S) Wells 1. The location will be planned so as to obtain the maximum safety benefit consistent with the rig configuration, well depth, terrain, prevailing winds, etc.. In setting up the drill site, the following criteria must be achieved in order to prevent having to relocate equipment. 2. The drilling rig will be situated on the location so that the prevailing winds blow across the rig toward the reserve pits. 3. The location will be larger to accomplish each job safely (i.e. large reserve pits, ample pipe racking turnaround, etc.). 4. Three cleared areas at least 75 meters from the BOP s upwind of areas will always be designated as the safe briefing area. During an emergency, personnel will assemble at this upwind area for instruction from their supervisor. 5. At least three sets of wind streamers on streamer poles will be located so as to give wind directions at tree top level, at drawworks level, and at a level 2.5 meters above the ground.

10 10 6. All wind streamers will be illuminated at night. 7. Logging units will be located so as to be at least 75 meters from the BOP area to eliminate congestion and the safety of the logging operations. 8. Mud tanks will be located away from the sub-structure in order to facilitate the movement of fresh air around the cellar area. 9. Electric power generators will be located at least 45 meters from the BOP s to reduce the hazard of explosion. 10. All electric wiring devices and lights will be checked and put in vapour Proof condition so as to reduce the possibility of explosion. Heaters used on the rig floor and doghouse will be of the flame-proof type and must be turned off after H2S is first encountered. 11. All windbreakers and rig curtains will be taken down when the drilling approaches the sour gas production zones. 12. Telephone and/or radio communications will be available at the rig. 13. Bug blowers will be available for use when required. 14. A map will be obtained showing all buildings in a 3 kilometre radius of the well site. All occupied buildings will be marked on the maps with the number of people occupying the building. Names will be listed and contact will be made after drilling begins, explaining the hazard and that evacuation might me necessary if an emergency develops. Just the fact that you have a heavily wooded section behind you does not mean that there may not be homes, livestock, or possibly a school only a short distance away. 15. Well planning will include the use of inhibitors in the drilling mud, such as zinc carbonate, etc., to reduce the reaction of hydrogen sulphide on the drill string, fluid end of pumps, chokes and piping. Inhibitors also reduce the amount of hydrogen sulphide that gets to the surface, reducing the odour and the offensiveness, making it possible for the crew to work more efficiently without air masks. Such jobs as laying out a core or other hazardous tasks call for the use of gas equipment, even though you have not had hydrogen sulphide odours at the surface. 16. An overbalance of mud in addition to the use of a good inhibitor can save many hours of rig time as this prevents H2S odor from getting to the surface. When air masks are worn, additional help such as roustabouts should be used so the men can work in pairs using the buddy system. This is necessary in heavy gas concentrations where a man may be overcome by gas and one would not know it. Recovery must be made in a short period or a man will suffer the after effects. 17. The police department having jurisdiction over the area, ambulance, hospital and doctors in the area will be contacted after drilling begins to let them know of the hazard and what actions they could expect should an emergency develop. Most doctors have

11 11 not treated H2S gas cases and on the initial visit, you will give the doctor all the information on this gas that you have. Rig Managers can request additional copies of this gas manual for loan to the doctors. 18. Personnel that have punctured ear drums will not be allowed to work in potential H2S environments as the gas can get into the lungs through this passage. Check on your men. Physical examinations will detect punctured eardrums. 19. A kill line of ample strength will be laid to a safe point so men and equipment can set up to pump into the well if necessary. Burn pits shall be located in opposite directions from each other so a change of wind direction will let you reduce the hazard by changing flow from one pit to the other. This gas seeks low areas. General Safety Precautions While Testing Wells Containing H2S 1. DANGER, KEEP OUT OF HYDROGEN SULFIDE (H2S) and DANGER NO SMOKING signs shall be displayed at the approaches to the well site and/or strategically placed 75 meters from the well bore. 2. DANGER KEEPOFF RIG FLOOR sign shall also be displayed in strategic locations to prevent unprepared and unnecessary persons from accidentally walking into an H2S contaminated area. Smoking is allowed in designated smoking areas only. a. Take every precaution possible to prevent the escape of this gas into the air. (Note direction of the prevailing wind). b. Keep unauthorized personnel from work area and away from drifting gas. c. Keep any animals away that may be nearby. 3. Every effort must be made to keep H2S flare lines lighted at all times. This may be done by the use of burning pots or a propane pilot light. ( Special flare gun shells can be used as a relatively safe means of lighting a flare.) 4. Locate doghouses, etc. according to prevailing winds. Check position and location of logging units and advise occupant of hazards of testing. 5. Provide adequate ventilation on rig floor. Remove wind walls at testing time and make use of blower fans at rotary and shale shaker. 6. Personnel shall be cautioned to be particularly alert for H2S in buildings, low places, around tanks, separators and in the cellar. Before entering suspected areas, make sure a test has been made to determine the percentage of H2S gas. 7. Use buddy system when possible. Wear a mask when testing for H2S.(Remember, H2S is heavier than air.) 8. Each employee must have a thorough knowledge of artificial respiration.

12 12 9. Each employee must know how to contact the nearest doctor and hospital. (have telephone numbers posted in the doghouse and clearly marked.) 10. Provide unobstructed passages and easy access from rig floor to drill stem test control head. 11. Flares and burn pits shall be at least 45 meters from the rig and other installations. Two flare lines shall be installed with proper valves in order to take advantage of changing directions of the wind. Three (3) sets of wind streamers shall be up. 12. Flow lines and flare lines shall be staked down. Flow lines shall be straight to burn pits, free of 90-degree turns. 13. Make sure the area around flares and burn pits is sufficiently cleaned to prevent brush and grass fires. It is easier to clear the space than to extinguish the fire. Ammonia Hydroxide (26 degree Aqua Ammonia) - Use to neutralize hydrogen sulphide. The use of this material and method is a partial control from removing hydrogen sulphide (H2S) from the drill stem after tests by use of an ammonia hydroxide solution. 14. Since the danger of poisoning to rig crews by exposure to H2S gas exists during drill stem tests, precautions will be taken against this eventuality, such as the provision and/or use of: a. Gas detector tests b. Ammonia to neutralize the H2S gas c. Breathing apparatus d. A resuscitator for emergency use NOTE: Keep resuscitator and oxygen bottles stored in a clean area, preferably away from the rig. CONTACT BETWEEN GREASE OR OIL AND PURE OXYGEN - NO MATTER HOW SMALL - WILL RESULT IN A VERY DANGEROUS EXPLOSION. Although items a, c and d, provide good adequate protection for crews, the use of this equipment alone is not only costly, but slows down operations since crews may have to wear masks during the complete trip after a drill stem test. Thus, the additional steps shall be adopted of using ammonia (NH3) to provide protection against H2S gas as referred to in (2) above. 15. Caution - there are three (3) possible hazards in using ammonia to neutralize hydrogen sulphide: a. It may invite crews not to wear their breathing apparatus when liquid portion of the d/s test is encountered. This would be wrong. At this time you cannot neutralize the H2S in the liquid by pouring the ammonia water down the drill pipe so at this point and with.001% (1PPM) or more, concentrations of H2S, breathing apparatus must be worn.

13 13 b. Wet stands (presently pulled and standing in the derrick) can be neutralized by pouring ammonia water in from the top (and washing of the floor at the bottom). Be sure that the plastic bottle or container holding the solution sent to the monkey board is rugged, well secured, and that the crew is kept back while transporting it to the derrickman. c. Under these and other normal conditions of use, ammonia cannot create a poison hazard for the workers. However, ammonia shall not be breathed over long and extended periods of time. Harmful ammonia concentrations will always warn one by its sharp and pungent smell. Materials and Equipment to be Available at the Rig 1. One 45 gallon drum of 26-degree Aqua Ammonia. 2. Metal spigot (faucet) and a stand for the drum to be raised at least 60 cm off the ground. 3. Two 22 litre (5 gal.) clean cans (with handles) for mixing NH3 and water (labelled and kept for this use only.) Two 4.5 litres (1 gal) markings shall be painted on the inside of each 22 litre can, starting from the bottom. (Dents or ridges inside the containers are helpful and more lasting.) 4. One lever or drum-type, 22 litre, metal container. This container into which the mixture can be poured will be placed over the box end of drill pipe above rotary table. 5. Three 4.5 litre heavy plastic, transparent bottles or jugs, each with handles and previously marked off or painted at intervals of one quart. (For Use on Derrick Only ). 6. A small, metal funnel for partially filling plastic bottles from ammonia drum spigot. 7. Two (2) signs, each 3 X 2-91 cm X 60 cm, one reading Danger Poison Gas - Keep Out. This is to be posted at the gate or road to lease, preferably on the road. The second sign, to read Danger Poison Gas Keep Off Rig Floor, is to be posted at foot of steps leading to rig floor. 8. Bug blower fans. 9. Procedure: The 50/50 Aqua Ammonia and water mixture shall be added to the pipe as soon as the control head is removed from the pipe after the tool has been closed. A sufficient quantity of this 50/50 solution shall be added to neutralize about five (5) stands (11.5 litres or 2-1/2 gallons of 50 /50 mixtures) to begin with, and after that, treat each stand before it is pulled from the hole. (Approximately 22-1/2 gallon of 50/50 mixture per stand.) It is not always possible to completely neutralize five stands in this

14 14 manner by only adding the calculated amounts. So at first, check with the H2S gas detector (sniffer) after each stand is broken out. Then if the detector still shows harmful presence of H2S gas, the pipe can then be immediately re-treated and the quantity of treatment increased if necessary. SPECIAL NOTE: The above treatment of H2S gas in the drill pipe with ammonia solution is possible only until the fluid from the formation in the pipe is reached. It is then necessary to reverse circulate the fluid out of the hole. Should the pump-out sub fail, it will be necessary to pull the rest of the way out of the hole with the crew wearing their gas protection equipment. NOTE: Each wet stand in the derrick will have been treated as soon as broken out. 10. In very cold weather, the amount of ammonia gas given off from the 50/50 solution will be lower. So, during cold weather conditions, the 50/50 ammonia solution shall be poured into the drill pipe before it has a chance to cool off. 11. Re-Emphasis: This method of neutralizing H2S is absolutely safe as long as gas alone is present in the drill pipe. As soon as liquid is encountered, it will be necessary for the crew to have breathing apparatus protection. SUBJECT: HYDROGEN SULPHIDE GAS Hydrogen Sulphide, frequently called H2S, is a colorless, heavier-than-air (relative density to air 1.189) and extremely toxic gas. At low concentrations, it has the smell of rotten eggs, while higher concentrations have a rapidly paralyzing effect on the olfactory nerve. For this reason, dangerous concentrations of H2S gas cannot be detected by smell. H2S is extremely toxic, approximately six times as toxic as carbon monoxide. It is also highly explosive when mixed with air between 4.3 to 46% by volume. Personnel involved in drilling and testing wells containing hydrogen sulphide gas should be familiar with the properties, hazards, and control of this gas.

15 15 In the event of an H2S knockdown the victim must be rescued following the seven step initial response strategy. 1. Evacuate the area Get to a safe area immediately. 2. Alarm Call for help. 3. Assess Do a head count, consider other hazards. 4. Protect Put on breathing apparatus before attempting rescue. 5. Rescue Remove victim to safe area. 6. Revive Apply rescue breathing, if necessary. 7. Medical Aid Arrange transport for victim to medical aid. When the victim is out of the contaminated area, get air into his/her lungs as quickly as possible by a resuscitator, or by mouth to mouth resuscitation. Without air, after three minutes severe and irreversible brain damage is a strong possibility. When the victim has been rescued and revived, treat the victim for shock; keep him/her warm and quiet. Do not let him/her go back to work or move around. Wash the eyes with clean water. The victim must be taken to the nearest hospital and remain under observation for 48 hours. The H2S booklet produced by Work Place Health and Safety is required reading by all employees. SUBJECT: HYDROGEN SULFIDE GAS - Hydrogen Sulphide Suspected 1. An operator and/or supervisor, before exercising an operational procedure, will: a. Assess the hazards of the operation b. Evaluate operation and consider methods of eliminating and/or replacing hazards by ensuring that: i. all equipment meets standards for H2S environment ii. all personnel are aware of their duties and know how to perform their respective tasks correctly

16 16 iii. all personnel know what evasive action must be taken if an uncontrolled release of sour hydrocarbon occurs. 2. Each worker will be informed of the characteristics of H2S and its dangers, safety procedures to be used when it is encountered or suspected and recommend first air procedures. 3. Instruction in the use of protective equipment available will be given to all employees. 4. Upon drilling into a formation suspected of containing hydrogen sulphide, a test will be made to determine whether or not the gas is present and the concentration level. 5. Do not try to determine the presence of H2S by its odor. The sense of smell is rapidly paralyzed by this toxic gas. 6. Personnel will watch out for each other. Where possible they will work in pairs. 7. Warning signs will be used at all times. 8. Adequate ventilation must be maintained to keep the gas removed from the work area. 9. Never enter an enclosed place where H2S may have accumulated without wearing proper respiratory protective equipment. If the worker is over an arm s length away, a safety belt will be secured to a life line and held by a responsible person who is in the clear. 10. Protective equipment will be readily available to those who work where H2S may be present. 11. Should anyone succumb to H2S, the following rules are critically important. 12. Don t jeopardize your own safety. Wear protective self-contained breathing equipment and move the victims into fresh air at once. 13. If the victim is unconscious and not breathing, immediately apply mouth to mouth resuscitation. Continue without interruption until normal breathing is restored. 14. Transport victim to hospital and/or summon a doctor. NOTE: practice the first ten suggestions and you are not likely to ever need number 11 because of an uncontrolled release of sour (H2S) gas. SUBJECT: HYDROGEN SULFIDE GAS - Hydrogen Sulphide Encountered Hydrogen Sulphide (H2S) gas may be encountered under a variety of circumstances and in large or small concentrations. It may be present during normal drilling operation, during a drill stem test, or if a blow out should occur.

17 17 If H2S is present in any concentration, the priority for deciding if work should continue shall be the risk of human life. A blow out is, of course, an emergency and the appropriate action is to evacuate the area and call Chinook Management, AEUB and RCMP. The Alberta Legislation governing exposure to H2S is as follows: 1. Threshold limit value 10 ppm eight hours exposure 2. Threshold limit value 15 ppm ceiling concentration reached, no further exposure permitted without the use of breathing apparatus 3. ppm- Parts per million When H2S is present: The TLV (threshold limit value) shall be followed A test for H2S shall be taken every half-hour and recorded in the tour book, unless a continuous monitor is present or H2S levels require the use of breathing apparatus. When Drill Stem Tests are being conducted, no one except those involved with the safe operation of the test are to be present on the rig lease area. NOTE: Refer to Section Emergency Response, Class V, H2S Exposure. SUBJECT: HYDROGEN SULFIDE GAS - Operations When Toxic Gas is Detected Operations When Toxic Gas is detected: The hydrogen sulphide (H2S) monitors will activate a siren and blinker lights when toxic gas is present When this occurs: Do not panic. 1. Hold your breath 2. Put on your gas mask

18 18 3. With mask on, help anyone needing assistance 4. Follow your supervisors instructions 5. Safety representative will immediately observe charts registering H2S concentration and will conduct other tests 6. If condition warrants, driller will secure rig, stop operation of rig and close blowout preventers. 1. Do not panic. 7. At this time, the Drilling Rig Manager will assist the operator personnel in assessing the situation, outlining a program of control, and assign duties. Follow his instructions carefully. Success of the plan depends on how quickly, thoroughly and effectively each man does his assigned duties. When the severity of the situation has been determined, all personnel will be advised. When H2S is at the surface a guard will be placed at the entrance to the location to keep unauthorized personnel from entering, and a check-in/check-out system for personnel entering and leaving the location shall be conducted. 8. All work that is done after H2S is known to be on the surface will be based on the assessment of the situation.

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