Hydrocarbons are organic compounds consisting entirely of carbon and hydrogen; there are many different kinds which result from differing molecular structures. Some of the most common hydrocarbons include methane, ethane, propane and butane. They are mainly found in crude oil. Extracted hydrocarbons in liquid form are called petroleum and in gaseous form are called natural gas. Hydrocarbons are the main source of the world’s electricity and gas production. Offshore oil rigs do pose a major hazard. Any or all of these events could occur:
- Fire and release of hydrocarbons
- Explosion resulting in the release of an explosive cloud
- Oil release into the sea
HSE’s Offshore Division (OSD) is the directive responsible for the offshore oil and gas industry. The OSD is responsible for regulating the UK’s Continental Shelf oil and gas rigs. The OSD tries to ensure that investigations of past hydrocarbon releases are thorough, so to avoid a re-occurrence. There have been 139 major and significant releases in 1999/2000. From 2005/2006 onwards hydrocarbon releases have plateaued to 70 to 80 per year. Offshore employers and the self-employed on rigs have a duty to ensure they work by the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR). DSEAR protects workers against the risk from fire and explosion. The safe production and processing of hydrocarbons is necessary.
Duty Holders (those responsible for maintaining the oil/gas rig) have a responsibility to consider the adverse health effects as well as the immediate effects such as fire and explosion. Any real side effects caused by hydrocarbons usually result in exposure of concentrations of thousands of ppm. Health effects include asphyxiation, narcosis (leads to unconsciousness), cardiac arrest and aspiration. Hydrocarbons with a higher molecular weight are more likely to produce a narcotic effect. Hydrocarbons may be released through intentional (e.g sampling, maintenance) or accidental (eg leaks from pipes or somewhere within the plant). If the breach was through e.g maintenance there should be respiratory protective equipment for staff, de-gassing and de-pressurising systems in operation to contain the release. Prevention is the way of managing accidental breach. There must be an identified escape route (outside of any confined spaces), alarms in all areas on the rig, disaster training and the use of respiratory protection. Respiratory protection needs to be within easy reach of staff and they need to have been trained in how to use this quickly, as the effect of hydrocarbons on the body can occur within a few seconds. On rigs there must be effective fire and explosion control to detect leaks early on. A temporary refuge area must be maintained to house workers temporarily in the event of hydrocarbon release.
Wildlife and ecosystems can be damaged through oil spills. Accidents can occur from crude oil leaking through the sea surface and from refined oil leaks from tanker ships. Spills at sea are much more damaging than on land because they can spread for hundreds of miles covering everything in a thin and deadly oily film. Vessels must be contained within effective pressure to contain the hydrocarbon. There should be risk based inspections to identify any signs of corrosion in the pipework.
The use of petroleum can react negatively with the environment causing the release of greenhouse gases into the air. Also, the earth only has a finite reserve of oil so there is concern over depleting this energy reserve and the effects it could have on sustaining future generations.