Deaths due to hydrogen sulphide on a jack up rig at Bombay High: an avoidable accident.

An enclosed space is an area with poor or no natural ventilation which is not designed for continuous occupancy, where access is limited and which may contain a dangerous atmosphere. Enclosed space atmospheres can be hazardous due to one or a combination of the conditions which includes oxygen deficiency; presence of toxic and/or flammable gases. When it is intended that personnel should enter or work in an enclosed space, care should be taken to create and maintain safe working conditions. The case report describes an incident on board an oil rig where the rig workers were exposed to noxious gases resulting in multiple fatalities. Work involved gas sampling/monitoring at various locations inside the "spud tanks" of the rig and certifying it free of noxious gases for marine surveyor's inspection. Contributory factors that have been frequently identified following enclosed space accident investigations are non-compliance with procedures, inappropriate equipment, poor supervision, complacency and over familiarity leading to short cuts being taken, detection and monitoring equipment not used or not working properly and improper action in an emergency. Preventive measures to avoid such accidents and create a safe working area are discussed.

Rescue of a saturation diver, unconscious due to an explosion underwater.

Evolution of "safe diving practices" introduced by the diving industry and regulatory authorities in the North Sea over the past 3 or 4 decades has improved the safety records of oilfield commercial diving considerably. However, accidents still occur. In an accident occurring underwater, the outcome is often fatal. For a diving doctor providing emergency medical advice to the industry, when a diving superintendent calls to say "I have a problem" indicates an emergency and a life and death situation for a diver in water. Making a quick decision after comprehending the situations is important to tackle the problem.

Saturation diver fatality due to hydrogen sulphide while working on a subsea pipe line.

In the offshore oil industry, Multipurpose Support Vessels with extensive diving capability are used for inspection, maintenance and repair of subsea pipelines. The diving industry has developed systemic safety checks and strict regulatory control after a number of fatal accidents in early years. However, accidents do continue to occur and, when involving divers in the water, are often fatal. Hydrogen sulphide (H2S), called 'sour gas' in an oil field, is produced by the action of anaerobic bacteria on sulphate containing organic matter. A highly toxic gas, it remains a constant danger for offshore oil industry workers who must remain vigilant. Crude oil and gas produced in these oilfields is called 'sour crude' and pipelines carry this crude with varying content of dissolved H2S to shore for processing. Divers are routinely called to attend to leaking pipelines and come in contact with this crude. Their hot water suits and umbilical lines are often covered with crude containing dissolved H2S. There is always a possibility that these may enter and contaminate the bell environment. Such a case leading to fatality is reported here.

A case of neurocysticercosis with an unusual presentation on high seas.

Every seafarer undergoes a medical examination prior to joining a ship. Some disorders cannot be detected and they may appear while at sea. Diagnosing and managing them becomes extremely difficult for the Master being the caregiver on board. Large crude carriers often perform long voyages and due to their sheer size, do not enter any port. Helicopter evacuation of a sick or injured crew is the norm. They operate under strict chartering time lines which do not permit deviation from course. A case of hemiparesis on left side of body in a young hitherto healthy seafarer which was later diagnosed as a case of neurocysticercosis is described.

Medical evacuation on high seas.

A previously healthy Indian male seafarer aged 34 years, presented with vague perianal symptoms to the Master on a Very Large Crude Carrier (VLCC) in the Pacific Ocean. Over a few days, his condition deteriorated, and the company's medical consultant ashore, based on telephonic consultation, transmitted information and photos, diagnosed the condition as a life threatening case of Fournier's gangrene. The ship was then almost 1140 nm from the port. The consultant instructed the Master to intensify antibiotic treatment and started necessary procedures for an urgent complex medevac. Arranged by the United States Coast Guard, it involved deployment of two helicopters, two fixed wing aircrafts and an air tanker. Helicopters needed to be refuelled mid-air to increase their range of operations. Rendezvous point was 478 nm from Santa Barbara, California. 3½ hours after lift off from the vessel, the helicopter landed at Santa Barbara airport and the patient was transported to hospital. State-of-the-art treatment ashore preserved both testicles and after long term recovery the seafarer was again fit for ship duty.

Evaluation of Heat Stress in Construction Site of Metro Rail in Chennai.

INTRODUCTION: Tunnel boring machine (TBM) is used for constructing a tunnel. Worn out cutting tools have to be changed under difficult working conditions. Temperature is high and the work is strenuous. Work is often carried out under increased atmospheric pressure to ward off water ingress. Workers are at a very high risk. AIM: To evaluate heat stress during hyperbaric intervention on TBM during Chennai Metro Rail construction. METHODOLOGY: One hundred and eighty-eight miners after a thorough medical examination worked under increased atmospheric pressure for more than 45,000 man hours. Mitigating actions to protect workers by reducing temperature and increasing ventilation. Medical monitoring was done to identify and treat potential victims. RESULTS: 52° C was the highest temperature recorded. Most times work was carried out at a temperature range of 34-45° C. CONCLUSIONS: Motivations of monetary gains, reduced working hours, and food supplements played a major role in work execution without any untoward incidence.

Compressed Air Working in Chennai During Metro Tunnel Construction: Occupational Health Problems.

Chennai metropolis has been growing rapidly. Need was felt of a metro rail system. Two corridors were planned. Corridor 1, of 23 km starting from Washermanpet to Airport. 14.3 km of this would be underground. Corridor 2, of 22 km starting from Chennai Central Railway station to St. Thomas Mount. 9.7 km of this would be underground. Occupational health centre's role involved selection of miners and assessing their fitness to work under compressed air. Planning and execution of compression and decompression, health monitoring and treatment of compression related illnesses. More than thirty five thousand man hours of work was carried out under compressed air pressure ranged from 1.2 to 1.9 bar absolute. There were only three cases of pain only ( Type I) decompression sickness which were treated with recompression. Vigilant medical supervision, experienced lock operators and reduced working hours under pressure because of inclement environmental conditions viz. high temperature and humidity, has helped achieve this low incident. Tunnelling activity will increase in India as more cities will soon opt for underground metro railway. Indian standard IS 4138 - 1977 " Safety code for working in compressed air" needs to be updated urgently keeping pace with modern working methods.