Occupational Health Hazard: A Case Study of Hydrogen Sulfide Hazard at Chevron United Kingdom

Subject: Health Care
Type: Process Essay
Pages: 12
Word count: 3224
Topics: Health, Management


Chevron United Kingdom (UK) is an oil and natural gas exploration and processing company that has 10 offshore oil producing field in the North Sea. It produces crude oil and natural gas on daily basis at an average rate of 40,000 barrels per day of liquid oil and 115 cubic feet of natural gas. Chevron UK has been operational for more than 50 years and contributes to approximately £ 2.71 billion to the economy of the UK (Alexander 2004).  It supports job requirements of the UK and international citizens by employing 51,727 employees. The operation of Chevron occurs in accordance with the Infrastructure Code of Practice (ICP) which determines the principles on which a third party can be involved in negotiation for exploration of oil and natural gas within the United Kingdom Continental Shelf (UKCS). There are a number of activities that take place from the drilling of crude oil until the final products are transported to commercial centers for sales (Cox and Cheyne 2000). These include: exploration, liquefaction, storage, conveyance from one stage to another, monitoring of the gas and crude oil through the vessels, manufacture of petrochemical products, addition of lubricants, and regasification. 

The working environment at Chevron such as oil and natural gas processing activities is characterized by high exposures to different forms of health hazards. Activities such as distillation of crude oil and natural gas, cracking of crude oil, combining, and reforming, are usually accompanies by high number of health hazards to the employees of Chevron. These hazards require that effective managerial measures must be incorporated to prevent the likely health impacts that can affect the employees in case of their exposure (Bouder 2010). A major form of health hazard that has been of concern is Hydrogen Sulfide (H2S). Due to the adverse health implications as a result of the exposure to this gas, it has been necessary to put measures in place to address the safety of employees at Chevron. This paper explains Hydrogen Sulfide as a health hazard at Chevron, the management practices that have been put in place to promote safety of employees from the gas, and a recommendation of the steps that the company can take to promote safety of employees to ensure their safety is enhanced above the present safety management practices. 

Hydrogen Sulfide as a Health Hazard and How it Has Been Managed at Chevron

Hydrogen Sulfide is found in oil and natural gas produced by Chevron and has to be effectively managed due to the health hazards it poses on people in the exploration and processing activities. H2S can be found in natural gas and oil wells, refineries, and pipelines conveying petroleum and natural gas before refinery. Generally, H2S is toxic and has a smell of a rotten egg. It has an irritating impact on lungs, nose, eyes, and throat (Jones 2014). When there is a high amount of H2S in oil and natural gas, it can be fatal upon exposure to employees specifically when they are not provided with protective equipment. The people who are exposed to H2S can tremble to death within a few seconds of exposure due to the failure of the breathing system. In areas where H2S leakages have occurred, employees have to be evacuated and only those with protective equipment can be allowed to enter and correct the problem. 

The density of H2S is higher than that of air (1.2 times denser) which makes it travel for a longer duration in the area near the ground and causing its exposure to humans who are in areas such as basements, ineffectively ventilated areas, underground gas storage tanks, and in facilities where oil and liquid gas processing take place. The major route through which exposure to H2S occurs is inhalation which results into the absorption of the gas in the lungs. Absorption through the skin does not result into a major health impact (Skrtic 2006). When one is exposed to H2S, the smell of a rotten egg can be sensed but when there is a continuous exposure in high concentrations, a person loses the ability to smell. This occurs in a rapid manner at high amounts of H2S and a person is likely to experience a total loss of the ability to smell. Another health hazard associated with Hydrogen Sulfide is its inflammability and the ability to explode. It can travel to areas exposed to sources of heat and ignite causing the production of toxic gases such as sulfur dioxide. If one is exposed to H2S, there is a likelihood of frostbite. 

H2S has deleterious health effects if it gets into the body. It can inhibit the cytochrome oxidase enzyme system from producing the enzyme which promotes oxygen utilization in cells. It can contribute to an imbalance of acid-base in the blood which can cause complications in the functions of cardiac tissues. Increased exposure has health effects that occur at levels that could be tolerated previously. When one is exposed to lower concentrations of H2S, irritations are felt in the eyes and one experiences a burning feeling and shortness of breath (Chou and World Health Organization 2003). These health impacts can be experienced for a number of hours or days, when one is working in areas with low concentrations of H2S. When one is exposed repeatedly to H2S for a long time, the impacts of the gas may include; eye inflammation, headache, irritability, difficulties in digestion, and loss of weight. Exposure to moderate quantities of H2S has impacts such as difficulty in breathing, dizziness, nausea, vomiting, coughing, and excitability. If there is a high concentration of H2S in the working environment, the affected person can experience shock, convulsions, unconsciousness, coma, or death. 

The Central Nervous System (CNS) is a major area which is highly affected in case of exposure to H2S. At high concentrations, it can contribute to depression of the CNS, stimulation of rapid breathing, impaired gait, and coma (Hughes and Ferrett 2011). High amounts of exposures to H2S can lead to insufficient cardiac output and high incidences of abnormalities. It can also cause a burning sensation on the skin, redness of the skin, inflammation of the skin, and frostbite injury. 

Evidence shows that exposure to H2S can result into Developmental Impacts which are associated with high likelihood of abortion. However, there is no evidence which shows that exposure to H2S can result into developmental impacts. 

A number of management practices have been put in place in order to manage the hazards due to H2S at Chevron in the UK. The first step has been to rescue those who are exposed to H2S and providing them with medical services. A commonly used measure in case of exposure to H2S has been the provision of First Aid to the affected employees. When H2S has been detected, the victims are usually evacuated from being exposed to more of the gas. Rescues with protective equipment are sent to fix the problem by wearing positive pressure self-contained breathing apparatus and other equipment which guarantee their safety. If the victims are not able to breathe due to the impacts of H2S, they are provided with cardio-pulmonary resuscitation (Alexander 2004). Contaminated clothing are removed from the victims and they are placed in an area where they can get further treatment. Victims whose eyes have been affected due to the exposure to H2S are flushed with large quantities of clean water for approximately 15 minutes. This is followed by the referral of the affected workers to the nearest health facility for treatment. 

Another commonly used measure for protection of employees of Chevron from the impacts of H2S has been the use of Engineering Controls. These involve activities of removing the substance from the air and creating a barrier between employees and the substance. For instance, Chevron has put in place enough ventilation in its facilities which enable easy air circulation and prevention of build-up of H2S in case of its existence in the oil and natural gas products. A majorly used engineering control is flaring. In this process of prevention of health hazards due to H2S, controlled burning is performed. This involves the removal of the waste gas from crude oil and natural gas in a safe manner (Cox and Cheyne 2000). However, the burning of H2S also results into the production of sulphur dioxide and also results into the emission of other greenhouse gases that have to be effectively controlled. As a result, flaring is a less popular method of preventing the health impacts of H2S exposure at Chevron. Chemical treatment is another commonly used form of engineering control as a management practice against hazards caused by H2S exposure. In this process chemicals are used to reduce the amount of H2S in crude oil and natural gas. The most commonly used process is the Claus Process which involves the extraction of H2S from gas stream by extracting and removing it after which it is converted a less toxic form in a chemical reaction. If there is H2S in off-gases from waste water treatment, scrubbers and filters are used to filter them. Chlorination is used to separate H2S from water by the use of Manganese greensand filers, ozonation, and activated carbon filters (Bouder 2010). Measures have been put in place at Chevron during drilling of oil and natural gas by performing H2S treatment in the drilling fluids and ensuring the right PH is achieved as a means of reducing the amount of H2S that undergoes recirculation. Caution is taken when handling the drilling fluid which is likely to have H2S exposure because it can move from the liquid into the vapor space in tanks in which the crude oil and gas is contained and can cause a health impact when the containers are opened. Sulfide cracking is another commonly used engineering control measure for H2S at Chevron in the UK.  This is the process in which vessels containing liquids and gases undergo corrosion and cracking due to the corrosive impacts of sulfur. It is a situation where sulfur contributes to embrittlement of the vessels and causes leakages of the liquids and gases in the containers (Bell 2013). Stress cracking has been prevented at Chevron by the use of corrosion resistant alloys in the construction of the vessels containing liquefied gases and petroleum in order to prevent health hazards due to H2S exposure. Most alloys used in the storage of oil and natural gas have been subjected to post-weld heat treatment in order to enhance their resistance to H2S corrosion. 

A number of administrative measures have been put in place at Chevron to promote safety of employees from the health impacts of exposure to H2S. These are: educating the employees about the hazards related to H2S, the symptoms of exposure to it, and training to monitor the facilities to prevent the likelihood of exposure to hydrogen sulfide (Jones 2014). Administrative activities have also incorporated the development of safe work procedures in environments which are exposed to H2S in order to prevent its impacts on people, maintenance of engineering equipment that may contain H2S and training employees to take caution while handling them. The use of personal or area monitoring equipment has been applied in areas where there is exposure to hydrogen sulfide. This equipment have been fitted with alarms that notify the employees in charge of the equipment in case of high concentrations of H2S. Monitoring H2S is another administrative measure used to prevent the health impacts of hydrogen sulfide at Chevron Corporation. This is done by setting alarms that can provide notifications in case of exposure to sulphur compounds such as H2S. Instruments have been calibrated as a means of ensuring they are in good operating condition to enable detection of H2S in the containers for liquefied gases and petroleum products at Chevron. 

The use of personal protective equipment has been used in all areas where there is likelihood of exposure to H2S as a means of ensuring their safety from exposure to the gas through skin contact, inhalation, or eye contact. This is due to the fact that this gas has a health impact when it gets is inhaled, ingested, or gets into contact with the skin (Skrtic 2006). Employees have been provided with respirators when working with drilling fluids which are exposed to H2S while performing oil and natural gas drilling activities. Employees of Chevron have been supplied with full-facepiece positive pressure aspirator when they are working in facilities that are exposed to high amounts of H2S in accordance with the recommendations of the National Institute for Occupational Safety and Health (NIOSH) which requires that purifying respirators must be used in an area which is exposed to more than 100ppm weight of H2S. 

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There are also a number of UK Health & Safety Executive (HSE) Legislations Regulations that have been complied with at Chevron as a means of ensuring safety of its employees from the hazards due to H2S exposure.  An example of these legislations is the requirement that organizations must observe the levels of exposure to H2S and prevent the health hazards on employees. It requires that when the level of H2S is above 100 ppm, it should be regarded as being Immediately Dangerous to Life and Health (IDLH). The management of Chevron has ensured no employee is assigned to work in an area with 100 ppm of H2S (Bouder 2010). Employees who enter areas with high concentrations of H2S have been supplied with  full-piece pressure demand supplied-air respirators and additional self-contained air supply as recommended by HSE. In case of an area with H2S concentrations below 100ppm, air-purifying respirators have been provided to employees in accordance with HSE requirements.  

Chevron has also complied with the Health & Safety Act of 1974, which requires that the employer has the duty to ensure the safety of employees at work place and prevent any conditions or incidences that can result into a threat to their health (Hughes and Ferrett 2011). This has been achieved by ensuring control of harmful emissions from the processing of oil and natural gas so that employees are not affected. The premises in which business activities at Chevron take place have been effectively controlled in order to prevent and harmful substances from entering into an area where they can cause harm to workers or the public. 

Chevron has complied with the HSE also recommendation that organizations involved in activities that can result into health hazards to employees must promote their safety by providing them with protective equipment which has ensured they are not harmed in case of the exposure to the hazards (Hughes and Ferrett 2011). It has also performed regular investigations of the levels of exposure to H2S hazards in order to improve the level of protection from the impacts on the health of employees. 

Chevron has ensured that equipment that are manually handled are identified whether they have hazardous substances that are likely to contribute to the health impacts on people and training employees on how to handle them with care. It has observed the Personal Protective Equipment at Work Regulations 1992 Act by providing employees working in hazardous environments must be with protective devices such as clothing, eye protection, and breathing equipment which ensure their safety from H2S exposure (Bell 2013).  All employees working in sections with high levels of H2S have been provided with eye protection, safety jackets, life jackets, and footwear. These equipment have been maintained to ensure they are in good working condition and effective in protection of people from health hazards. 

A number of recommendations have been made which will enable Chevron to achieve a higher level of protection of its employees from the hazards due to H2S. It is recommended that it should set the exposure limits for employees in accordance with HSE requirement which states that the maximum exposure limit should be 10 ppm in an 8-hour shift exposure. This should be applied to all workers who are directly and indirectly affected by the H2S. It is also recommended that there should be increased research and development (R & D) at Chevron that focuses on providing the employees with the latest techniques of management of H2S exposure at Chevron. This is due to the fact that the hazards due to H2S will be a continuous threat to the health of employees as long as Chevron continues to produce oil and natural gas in the UK. It is recommended that a code of practice should be created which determines the safe work procedures in areas where there are high concentrations of H2S. The code of practice should focus on the persons responsible for the performance of tasks in those areas, the procedures to be applied in order to work safely, the training procedures that one needs to undergo before working in such areas, and the emergency procedures that need to be followed in case of accidental exposure to H2S. 

While there are presently monitoring efforts in the management of exposure to H2S at Chevron, additional exposure monitoring practices need to be implemented. Chevron should install exposure monitoring equipment in its oil and natural gas pipelines and storage facilities. These monitoring instruments should be adequately calibrated and maintained in accordance with the instructions of the manufacturer. The instruments should be made operational in a proper manner and inspected in regular basis to determine whether it is able to provide the required notification in case of high concentrations of H2S. It is recommended that all employees of Chevron should be provided with training on characteristics of H2S, its physical and chemical characteristics, impacts on health, and measures that can be used to achieve personal exposure to it. They also need to be trained on proper use of safety equipment to prevent contact with H2S when performing their tasks in the company. It is recommended that employees of Chevron should be informed to communicate to the relevant authorities in case they identify high amounts of H2S in their working environment in accordance with the HSE risk communication directive. 

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This paper examines the Hydrogen Sulfide (H2S) as a health hazard at Chevron Corporation in the UK. It is found that H2S is produced along with crude oil and natural gas and can affect the health of employees if measures are not put in place to protect them. This is due to the impacts of H2S on health such as impaired breathing, cardiovascular complications, and impaired sight if one is exposed to it. Consequently, measures have been put in place to ensure employees are protected while working in areas likely to have high amounts of H2S. The main measures have been the use of protective equipment such as eye protection, foot protection, and life jackets. Chevron has also ensured compliance with the HSE regulations such as not assigning employees to work in areas with 100 ppm levels of H2S and controlling harmful emissions which can have an impact on employees’ health. The recommendations that have been made to improve the levels of safety of employees of Chevron from H2S exposure include: creation of a code of practice which prohibit entry into areas with high levels of H2S, intensifying monitoring efforts for occurrence of H2S in its facilities, and improving communication to the relevant authorities in case of exposures to H2S. 

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  8. Skrtic, L., 2006. Hydrogen sulfide, oil and gas, and people’s health. Energy. 
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