Marine pollution from ships is a major environmental hazard. The International Maritime Organisation (IMO) within the United Nations is responsible for ensuring compliance with the conditions set out in The International Convention For The Protection Of Pollution From Ships, 1973 (updated 1978) known as MARPOL, on the prevention of pollution and a speedy response to incidents that occur. MARPOL covers the leakage and spillage of oil and other harmful and noxious substances into the ocean. Annex 1 of the Convention specifically relates to oil pollution and that became the focus of a separate IMO convention on readiness, response and co-operation in dealing with major oil spills and led to the formulation of the Manual On Oil Production. Governments too have their role to play in encouraging oil and tanker companies to work in a way that seriously limits the potential for disaster and can achieve this by providing financial benefits or taxation incentives.

Irrespective of whether the issue is prevention of pollution or a response to an incident, safety considerations for tanker owners, off-shore oil installation companies and marine pipeline firms fall under a number of categories including the:

The introduction of MARPOL carried the need for double bottoms and double hulls, plus other specific design requirements, in all tankers with an oil carrying capacity in excess of 5000 gross tonnes. Clearly the industry needed time to adapt and the phasing in of the measure was due to end at the close of 2015. A double hull calls for two layers of watertight hull surface; in effect two separate tanks, with space between the tank walls that could be filled with ballast. Whilst double hulls will not prevent leakage in the case of a major incident they do have the potential to seriously limit the loss of oil into the ocean.

Governance also has a major role to play in preventing oil pollution and recording activities is a key part of that. Every ship, other than oil tankers, with a gross tonnage in excess of 4000 and oil tankers capable of carrying over 1500 gross tonnes must record details on the:

In addition, oil tankers must record the loading, unloading and transference of oil cargoes.

Analysis of both minor and major oil spills has demonstrated a disproportionate focus on engineering and technological developments when in fact 80% of oil spills involve some human error, so human action is also crucially important. The International safety Management Code (ISM) requires proper maintenance and working standards , such as the regular inspection of hulls. It could be further improved if it specified, for double hull tankers, which processes must be performed and at what intervals. As it stands it does recommend maintenance procedures in line with tanker type and particularly in relation to corrosion; which was one of the major factors that led, in 1991, to the discharge of 5.4 million gallons of crude oil off the West Coast of Australia by the Kirki. Interestingly, research suggests that technological innovations and engineering improvements do not necessarily reduce human error where it occurs. This is because, as technology becomes more advanced, it carries the potential for poor decision-making and error unless the personnel operating the systems have a proper understanding of how it functions.

The International Convention for The safety Of Life At Sea (SOLAS) deals with the prevention of marine incidents cause by human error. Its provisions include that;

In addition to the above, the Standards of Training Certification and Watchkeeping Code requires all mariners involved in the transportation of oil to be fully trained to carry out the requirements of their employment to the highest standards. Furthermore The Oil Companies International Maritime Forum (OCIMF) provides certification and self-improvement programmes to increase safety and encourage sound working practices for tankers. This is underpinned by the Ship Inspection Report (SIRE) which provides for the inspection of vessels by independent examiners. This is further assisted by the Tanker Management Safety Assessment, a benchmark against which tankers are assessed.

Adoption of the dual barrier system by the off-shore oil industry was a significant prevention measure against the leakage of oil from oil wells. The system protects the oil reservoir and environment with two independent barriers. If one barrier fails the other becomes operational.

This had been in use in land-based wells for almost a century before it's use in off-shore rigs from 1960. Since then, a series of adaptations and improvements have led to the effective use of BOPS at sea. One type of BOP sits on the sea bed whilst the other is sited between the riser pipe and drilling platform. As BOPs became more advanced they started to contain a greater number of non-dependent cut-off mechanisms; Pipe Rams and Shear Rams. If all else fails Shear Rams are capable of cutting through the delivery pipe. BOP systems continue to develop and experts believe that the inclusion of two shear rams should be mandatory, together with back-up systems that offer automatic, maximum control of the BOP.

Improvements and a better understanding of the limitations and operation of casings has helped to improve prevention of pollution from oil rigs. Casing is the large diameter pipe that is inserted into the bore hole and held in place by cement which provides support, particularly for the upper formations of the structure, and it facilitates the use of drilling fluids. Casing is effective in providing zonal isolation when it is required, and sealing-off high-pressure zones from the surface, avoiding the possibility of blow out.

Best practice for marine pipelines is promoted by the International Association Of Oil And Gas Producers, and The International Regulatory Forum (IRF), which has at its disposal highly experienced off-shore regulators from all over the world. In Britain, The Off-shore Petroleum And Pipelines (Assessment of Environmental Effects) Regulations implement Directive 2003/35 of the European Council, which is backed by supplementary guidance, including information on oil pollution emergency plans and environmental review inspections. In the US The Pipeline And Hazardous Materials Safety Administration is responsible for implementing The Oil and Pollution Act 1990.

Marine pipelines are no longer in their infancy and the industry continues to build up a great deal of expertise and a better understanding of the large number of factors that must be taken into account; such as the ecology of the area, oceanography etc. It is for this reason that multidisciplinary teams work together to ensure the highest standards of safety. The construction phase of the pipeline offers the best opportunity to mitigate the risk of oil pollution by taking advantage of the very latest technology. Today, pipes are constructed from steel with a high strength yield and joints are subject to full penetration welding. The pipelines are often encased in concrete with cathodic protection (a continual current of low priority voltage working against the build up of corrosion) internally. Devices knows as Pigs are propelled inside the pipe to counter the build up of sedimentation and other deposits.

Lessons have been learned from previous incidents involving tankers, off-shore installations and pipelines, and thankfully as major incidents decline the future looks bright. All three facets of the industry have long histories, and experience continues to grow along with technological innovation. As the industry continues to strive to cut the incidence of human error perhaps it is time to begin to think further about what safeguards there are to prevent oil pollution when natural disasters like earthquakes and tsunamis occur; and, moreover, how to mitigate against the challenges globalisation brings and the ever present threat of global terrorism.