The MSA is responsible for maintaining a nationwide capability to respond to marine oil spills of any size.

We have a base at Te Atatu, Auckland , the National Oil Spill Service Centre (NOSSC) and work with Regional Councils to provide a co-ordinated response capability. Oil spill equipment, including the national pool of large and specialised equipment, is stored there.

Staff at NOSSC manage the National Marine Oil Spill Contingency Plan, oil spill response equipment and provide training for people in MSA and from around the country who are likely to be involved in oil spill response, such as district and regional council staff and port company staff.

Each regional council has a stock of the equipment needed to clean up oil spills within their regional boundaries and particularly within their ports. This is supplied by the Oil Pollution Fund and is overseen by MSA.

By training people and equipping regions, the MSA is able to ensure there is an efficient oil spill response capability on a regional level. In the event of a major oil spill there is also a large pool of trained responders on call and equipment on hand to get the response effort underway immediately.

The Director of Maritime Safety appoints a National On-Scene Commander, who is responsible for leading the onsite response to a large marine oil spill, and two support teams are then established to assist these persons during a response. The Director's Advisory Team provides legal, media, nautical, financial and technical advice to the Director of Maritime Safety and backup support to the National On-Scene Commander. The National On-Scene Commander's Incident Command Team provides on-site planning, operational and logistical capability to clean up a large marine oil spill.

Oil Spill Response Objectives

The primary objectives of an oil spill response are:

•  to ensure the safety of people
•  to prevent further pollution from the marine oil spill; and
•  to contain and clean up the marine oil spill as far as practicable

Oil Types Most Likely to Spill in New Zealand

There are lots of different types of oil which are both transported by sea and used onboard vessels. The ones most likely to be spilled in New Zealand are,

• heavy fuel oil
•  light fuel oil
• marine diesel
•  petrol
•  crude oil

The risk of a crude oil spill is relatively small, compared to the other types, as New Zealand does not have large crude oil tankers transiting its waters, other than at the Marsden Point Oil Refinery in Whangarei and the offshore oil wells off the coast of Taranaki .

What Happens when Oil is Spilled at Sea?

Crude oil is a naturally occurring substance and if left untreated in the water it will eventually break down. It is broken down by the combined action of the sun, sea, oxygen and bacteria. Refined oil if left untreated will also eventually breakdown, but some of the heavier refined oils take longer to do so.

However, in a large oil spill significant environmental damage could occur if no action was taken.

When there is oil in the water a number of physical and chemical changes occur to the oil that affect the efficiency of the oil spill response and clean up operation.

The oil spill response team must understand the composition of the oil they are dealing with to establish how it will react to the various clean up options.

Significant elements for consideration are specific gravity (how dense the oil is), surface tension, viscosity (thickness), pour point (the lowest temperature at which it will pour) and flash point (temperature at which its vapors will ignite).

Prediction of Oil Movement and Impact

One of the important challenges for any response team is to predict where and how fast the oil may move.

Visual information is gathered on the oil slick, usually from the air, along with detailed local information on tides, currents and weather forecasts.

With this information, we can predict the movement of the slick over time. One of the techniques for analysing the information, that is just starting to become available, is computer-modeling.

Equipment

The equipment used in an oil spill response is stored and maintained at the MSA's National Oil Spill Service Centre in Te Atatu, Auckland , as well as with regional councils around the country.

Equipment can be mobilised quickly from anywhere in the country and transported by road and air to the scene of an oil spill.

Additional response equipment can be sourced from Australia , East Asia and England if necessary.

Clean-Up Options

The main clean up options considered in New Zealand are:

•  allow oil to break up naturally
•  mechanical action
•  dispersants
•  containment
•  recovery
•  shoreline clean up

In all cases it is a balance between removing all the oil and causing minimum harm to the organisms in the area being cleaned.

Allow Natural Break Up

If the spill is a good distance from shore and unlikely to cause damage to marine wildlife or the environment, the best response may simply be to allow the oil to disperse naturally. The ocean contains bacteria which break down the molecular structure of oil into less complex substances that are not hazardous.

In this situation, the only actions taken may be to report the incident and then monitor the movement of the oil and its rate of dispersal.

Mechanical Action

This involves using other vessels to churn up the water to assist in breaking up the oil, which can then be left to disperse naturally.

Dispersants

Dispersants are compounds which assist in the break up of the oil in the water, like a detergent in washing up water. However, oil spill dispersants used in this country are about 10 times less toxic than dishwashing detergents.

The chemical compounds which make up dispersants used in New Zealand include alcohols and glycols, in some cases diluted with water. The type of dispersant used would depend on the type of oil which has been spilled.

Any dispersant used in New Zealand marine waters, are approved in accordance with the marine protection rules. The MSA consults with regional councils, the Department of Conservation, environmental and wildlife advisors and local iwi before any dispersant is used.

The two main methods of applying dispersant to an oil slick are surface and aerial application. The method used will depend on the size and location of the oil in the water and the available resources.

Surface application involves using vessels in the water which are equipped with spray rigs. This method may be used in smaller spills and nearer the coastline.

Aerial application can be carried out from small fixed wing aircraft or helicopters which are fitted with spraying equipment. This method is usually used in large spills (particularly if out to sea).

For shoreline clean up and in accessible areas, dispersant may also be sprayed from a back pack.

Containment

With some oil spills the first priority may be to contain the oil to limit the impact on the environment. Once contained the oil can then be recovered and removed for disposal.

To contain an oil spill the most common piece of equipment used is a boom. A boom is simply a barrier which is anchored in to place and floats on the water. There is some surface area of the boom above the water to collect the oil and a skirt below the water to stop the oil moving under the boom.

There are a number of different types of boom which can operate in differing conditions and environments.

Booms are ineffective in heavy sea conditions and can be difficult to deploy successfully on rivers or waterways with strong incoming and outgoing tides.

Recovery

Once the oil has been contained, work can then start on recovering the oil from the water.

Mechanical skimmers are used to remove the oil from the surface of the water, using a variety of scientific principles to separate the oil from the water.

Wind and sea conditions have a strong influence on the efficiency of skimmers. They work best in smooth waters with little or no wave action.

Sorbents are another tool which can be used in oil recovery, in conjunction with skimmers, or when conditions mean that skimmers can not be used.

Sorbents are porous materials that suck up oil like a sponge. They can be in the form of booms, sheets, pillows and pads.

They can be made of natural organic material such as peat moss, straw, hay, sawdust and wool. Mineral based sorbents are made of material such as vermiculite, perlite and volcanic ash. Synthetic sorbents are generally made from polypropylene or polyethylene.

Once saturated a sorbent item must be carefully removed from the water to avoid contaminating oil-free water and then disposed of appropriately. Synthetic sorbents can be wrung out and reused. As much oil as possible should be removed from the sorbents before being reused or disposed of.

Shoreline Clean Up

In some cases it is not possible to prevent the oil reaching the shoreline and so the oil spill response is focused on minimising long term damage and clean up of the area affected.

Shoreline clean up is very labour intensive and therefore costly. It has been estimated that up to 50 percent of the total cost for some spills can be directly attributed to beach and shoreline restoration.

The success of a shoreline clean up will be influenced by the type of area involved. Sandy beaches can be cleaned using heavy machinery, such as diggers, as well as by manual raking and shoveling.

However rocky shorelines and areas with jetties and marina may require high pressure water spraying, low pressure washing and/or intensive hand cleaning to remove the oil.

Efficient shoreline clean up would normally only happen once there is no further risk of oil spill.

Effective oil spill clean up will involve environmental experts and detailed analysis of the affected area.

Wildlife

An oil spill can have a detrimental impact on wildlife and therefore every spill response plan must ensure there is an effective wildlife rescue, treatment and rehabilitation program.

The MSA has established an oiled wildlife response plan and Massey University is responsible for co-ordinating a specific wildlife response on behalf of MSA. This involves establishing a wildlife rehabilitation centre where injured or sick wildlife can be assessed, cleaned if necessary and prepared for release back in to their natural environment.

The Department of Conservation advises the MSA on sensitive areas which should be protected from the impacts of an oil spill, along with details of species of birds and other wildlife which may be in danger.

Disposal

Once an oil spill has been contained or when the shoreline clean up is underway, the recovered oil, oily debris and contaminated beach material has to be properly disposed of.

The recycling and disposal options selected for oily waste will depend upon the types and volume of waste generated from the response operation, storage, treatment and disposal technology available, environmental law and the cost of each option.

All waste must be disposed of in an environmentally sensitive manner in accordance with the Resource Management Act 1991.

The oil industry in New Zealand has formed the Used Oil Recovery Group (UORG) to provide for nationwide responsible collection and management of used oil. The UORG comprises: BP Oil NZ Ltd, Shell NZ Ltd, Castrol NZ Ltd, Caltex Oil (NZ) Ltd, Milburn NZ Ltd, the Ministry for the Environment and the Ministry of Economic Development.

Winding Down the Response
Winding down the response involves the recovery, cleaning and maintenance of all equipment used during the clean up, demobilisation of all personnel involved in the response and the completion of all documentation associated with the spill.

Monitoring of the environmental impact of the oil spill may continue for some time, ensuring the safety of wildlife, measuring the toxicity of sea food and gathering information on the recovery of the site.