Oil Pollution

What is oil?

Petroleum oil is formed over millions of years deep under the ground from the remnants of forests and from a mixture of comparatively volatile liquid hydrocarbons (compounds composed mainly of hydrogen and carbon with some nitrogen, sulphur, and oxygen) that occurs in the Earth's crust.  While it is a naturally occurring substance, it can be highly toxic and it burns fiercely. 

Oil is petroleum in any form including crude oil, fuel oil, sludge and refined products such as diesel and kerosene.

Oil is used as fuel to run many types of engines for cars, planes, ships, tractors and trucks, and is also used to generate a large portion of the world's electrical-power supply.  Petrochemicals derived from petroleum are the base for solvents, paints, plastics, synthetic rubber and fibres, soaps and cleansing agents, waxes and jellies, explosives, and fertilisers.  Asphalt from petroleum is used to surface roads and highways.  Petroleum is also used as a lubricant in a great variety of machines.

Why is the risk of a marine oil spill in Northland so high?

Large oil tankers (some of which can carry upwards of 100,000 tonnes of oil) bring crude oil from overseas to New Zealand’s only oil refinery at Marsden Point near the entrance to Whangarei Harbour.  The oil is discharged from the tankers to the refinery where it is then refined and transformed into various petroleum-based products.  These products are either then transported to Auckland via a big pipeline or transported by coastal tankers to other ports around the country, where they are then distributed to the consumers.

A large oil tanker arriving in Whāngārei Harbour.A large oil tanker arriving in Whangārei Harbour on its way to discharge crude oil at the refinery.

In addition to tankers coming into the refinery, there are also a significant number of general cargo, container and log and woodchip ships that travel to and from the main ports of Marsden Point, Auckland and Tauranga right here on our eastern doorstep.  Given the expansion of these ports in the near future, significant increases in shipping movements are expected.

A ship loading at Port Whangarei.A ship receives woodchip alongside a berth at Port Whangārei, Marsden Point.

The majority of Northland’s commercial shipping activities are based at Port Whangārei, Marsden Point and the refinery facilities at Marsden Point.  On average there are 100 oil tanker visits and 100 non oil tanker ship visits to these two facilities each year. There are a further 110 visits per year made to the Portland cement out-loading facility and a largely transient fishing fleet where numbers vary between 20 - 40 vessels operating from facilities in the upper Whangārei Harbour and in other Northland harbours.  There are also on average 30 commercial cruise ships that visit the Bay of Islands each year.

Both the Poor Knights Islands and the Hen & Chicken Islands are very close to the navigation routes of ships travelling to and from these ports, and up until recently a large proportion of these ships travelled between the Poor Knights Islands and the Tutukaka coast. 

A couple of reasonably significant oil spills in this area in the late 1990’s resulted in a ban being imposed on vessels over 45 metres in length prohibiting them from travelling through the area between the Poor Knights Islands and the mainland.  This is called a Mandatory Area to be Avoided.

Map showing the Mandatory Area to be Avoided.In 2004, Maritime New Zealand established a Mandatory Area to be Avoided that extends from land between Bream Head and Cape Brett out beyond the Poor Knights Islands.

As well as all the oil tankers, the ships, and the fishing vessels, we also have a very high number of recreational yachts, launches and runabouts.  By having all these vessels here in Northland makes us the most at-risk region in New Zealand.

Likely sources of oil spills

The majority of oil spills reported are investigated and evaluated and in most cases the source cannot be identified. 

However, these are examples where the source has been identified:

  • vessels sinking, listing or grounding account for about 10% of marine oil spills
  • discharges of contaminated bilge water from vessels account for about 15% of all marine oil spills
  • accidents occurring the refuelling of vessels account for 15% of marine oil spills
  • intentional spills into the storm water drains, spills from motor vehicle accidents and road runoff during heavy rain events can all lead to small oil slicks on the water.  While these account for 15% of the oil spills reported, they are not classified as a marine oil spill because the source of the spill did not originate from vessel or refuelling facility.  Costs in responding to these incidents are met by the Council unless the spiller can be identified. 

Fishing boat grounded on rocks.This fishing boat grounded on rocks at the entrance to Mangonui Harbour after its mooring parted during a storm.  A small diesel spill resulted.  The slick was left to disperse in rough seas on an outgoing tide.

What resources and activities are most at risk?

Northland has one of the most beautiful and pristine coastlines in New Zealand.  Some parts of it like the Whangārei Harbour and the Bay of Islands are enjoyed by thousands of people, particularly during the summer months, occupied in fishing, swimming, diving, sailing, surfing and shellfish gathering activities.  And so it is very important that the coastline and the marine environment are protected from pollution, especially oil spills.

Marine oil spills, even very small spills are likely to cause environmental damage, have impacts on social, cultural and amenity values and may interfere with the commercial and recreational use of the coastal environment.

While an oil spill on exposed sandy beaches and rocky shores would be unsightly, these would most likely recover more quickly then say the estuarine areas of our upper harbours.  This is because the wave action would help agitate, disperse and break down the oil.  This would assist with clean up operations.

The most sensitive parts of the coastal marine area are our estuaries and harbours.  The vegetation growing in these areas, such as mangroves, eelgrass and salt-marsh are very sensitive to oil pollution and do not recover that well.  This vegetation plays an important part in the environment by oxygenating estuary waters, trapping sediment and offering a safe shelter for many varieties of fish, invertebrates and birds to live and to breed.  Estuaries are usually dense with vegetation and access is always tricky, so any clean-up operation would be extremely difficult if an oil slick floated in to coat the mangroves and their breathing roots.

The effect of oil on sea birds can be devastating. The oil clogs to their feathers causing the birds to lose their waterproofing. Thin oils are also highly toxic. The birds might swim through the film of oil without problems but then die once they go back to their nest and start preening. The effect on wildlife can continue for a long time after obvious signs of the spill have disappeared.

Oiled bird.An oiled bird washed ashore.

Marine mammals such as seals coming into contact with oil after surfacing may be killed outright. Oiled wildlife not killed outright can be successfully cleaned and rehabilitated but it is a long process which can take up to six weeks. The animals and birds must be cleaned thoroughly, putting them under a lot of stress which could kill them.

The Poor Knights Islands marine reserve is another area that is highly sensitive to oil pollution.  While it is characterised by exposed rocky shores which would recover reasonably quickly from an oil spill, the marine and bird life living in and around the islands are special and internationally important, and are therefore particularly vulnerable to oil pollution.

The effect on people and amenity values are just as important as those on the natural environment.  The greatest hazard to human health from oil spills is the risk of explosion or fire at the spill site and also the inhalation of oil vapours.   Oil fumes can cause headaches, dizziness, nausea, vomiting and abdominal pains. Oil on skin can lead to rashes and irritation.

Now just imagine this. Two ships have a head-on collision out in the middle of Bream Bay.  One of the ships is an oil tanker, fully laden with heavy crude oil on its way in to Marsden Point to discharge its cargo at the oil refinery.  It is badly damaged and spews hundred of tonnes of ghastly, smelly black toxic oil into the sea. 

Within several hours, the white sandy beaches at Ruakaka and Ocean Beach are covered in oil.  Hundreds of sea-birds, some of them endangered species, are smothered in oil and many become fatalities.  Residents living in the nearby coastal communities are forced to leave their homes due to the toxic fumes coming from the oil.  All the beaches in the vicinity are closed in the interests of public safety.  There are restrictions placed on shipping, port operations and recreational boating activities in the area.  And fishing and the taking of shellfish are banned for health reasons.

Not a pretty thought is it?  But this could very well happen one day and when it does we need to ensure that we will be ready to clean it up!  A major shipping disaster would quickly become a national scale emergency.

What is the NRC role in oil spill response?

The Northland Regional Council is responsible for responding to oil spills in the coastal marine area (extending 12 miles out to sea from the Northland coastline), that exceed the clean-up capability of the person responsible for spilling the oil, or where the person responsible for spilling the oil cannot be identified.

In these situations, the Regional On Scene Commander assumes responsibility for the control and management of the oil spill clean-up operation.  The Regional On Scene Commander decides whether any such action should be to prevent further pollution from the oil spill and to contain and clean up the oil in accordance with the Marine Oil Spill Contingency Plan for Northland.  In Northland, we have three Regional On Scene Commanders.   A roster operates so one of these people is on call at any time to give advice or assume command in the event of an oil spill emergency.

Fortunately, there have been no significant oil spills in Northland in the past several years and the frequency of reported marine spills in general has continued to decrease.  This is largely the result a number of initiatives including the implementation of national and international environmental and industry standards, the production of “voluntary codes of practice” and the provision of information and educational material by regional councils and Maritime New Zealand. 

Preparedness in case of a spill

Under the Maritime Transport Act 1994, the Northland Regional Council is required to maintain a capability of oil spill preparedness in case a response to a marine oil spill is required.

Marine Oil Spill Contingency Plan for Northland

In accordance with standards provided by the Maritime Transport Act, Marine Protection Rules and any other guidelines issued by Maritime New Zealand, the NRC is required to produce, maintain and implement a Marine Oil Spill Contingency Plan.  This plan details standard operating mobilisation and response procedures, responsibilities and powers of all those involved in a response, regionally based oil spill response equipment and manpower available during a response, and the resources that are most at risk, particularly those in sensitive areas.  The primary objectives of the plan are:

  • to prevent further pollution from the marine oil spill; and
  • to contain and clean up the marine oil spill in a manner that does not cause further damage to the marine environment, or any unreasonable danger to human life, or cause an unreasonable risk of injury to any person.

The plan is subject to regular updates to improve its content.  These reviews are carried out after every major exercise or incident to ensure that the information within the plan is as current as possible.

Oil Spill Response Team

Response team oil spill exercise.Some of Northland's oil spill response team take part in an exercise to deploy the Ro-boom. In our region we have an experienced and well trained team of 60 odd people ready to respond to a marine oil spill at any time.  This team is largely made up of Council staff, but also relies on expertise from people at the New Zealand Refining Company, North Tugz, Northport Limited, Department of Conservation and wildlife agencies like Whangārei Native Bird Recovery Centre and the Ornithological Society of New Zealand.  These people have attended specialised training courses run by Maritime New Zealand down at the National Oil Spill Service Centre in Auckland.   Additionally, regional and national equipment familiarisation and scenario based desktop exercises are held regularly to ensure the response team maintains an acceptable level of knowledge and expertise.

Several of the Northland response team are also part of the national oil spill response team which has been set up by Maritime New Zealand to respond to a large spill anywhere in the country that was beyond the capability of that particular regional council.

Oil Spill Response Equipment

A large quantity of oil spill response equipment has been provided by Maritime New Zealand. The equipment is stored down at Marsden Point with a lesser amount kept in the Council workshop at Opua.  The equipment is regularly audited and maintained by Council staff to ensure that it is ready to work at any time.

The equipment inventory includes:

  • Specialised wildlife equipment for capturing and cleaning birds
  • Pillows, booms and pads made of material which absorbs oil but not water
  • Booms for deflecting or containing oil
  • Mechanical equipment for skimming oil from the surface of the water
  • Temporary storage tanks for storing the oil once it has been collected
  • Dispersants and dispersant application sets to spray on the oil either from a vessel, plane or helicopter
  • An oil skimming recovery vessel “Taranui”.


Ro-boom in water during an oil spill exercise.The Ro-boom being deployed here during an oil spill exercise, is used to deflect or contain oil.

If additional equipment and personnel was needed, then we can call on Maritime New Zealand to assist as they can source further equipment and people from all around New Zealand and from overseas if need be to supplement the response.

Types of oil pollution

Spilled oil spreads quickly and its movement will be determined by the tides and current as well as wind speed and direction. Oil will move at the same speed as the water carrying it and about 3% of wind speed. Crude oils are complex and variable mixtures of hydrocarbons of different molecular weight and structure. Crude oil may contain as many as 300 different compounds.

Types of oil commonly transported or used in Northland and the likely time to disperse naturally are:

Oil types Time to dissipate naturally
Petrol A few hours to 1 day
Aviation gasoline A few hours to 1 day
Jet fuel/kerosene Up to 1 day
Light marine diesel 1-2 days
Light fuel oil 1-4 days
Medium fuel oil 1-7 days
Heavy fuel oil 1-2 weeks
Bitumen and crude oils Months but will probably sink out of sight if not cleaned up


There is a great deal of difference in crude oils depending on where in the world they come from. A crude oil database has been compiled from oil companies around the world showing the different physical and chemical properties of their products. This information helps the response team know what they are dealing during a response. The different mixtures affect how the oil behaves on water and can determine the way in which it can be cleaned up.

Oil whipped up with water forms a chocolate mousse effect.Oil whipped up with water forms a chocolate mousse effect as shown above at the Poor Knights Islands. When oils are spilled, they are subject to weathering and the prevailing environmental conditions. This will affect how long they remain a problem.  Some oils will evaporate or disperse naturally within hours while others will persist in the environment for much longer. Until the oil is dispersed, it will move according to the wind, wave, tide and currents.

Some of the lighter grades of fuels (such as diesel) have vapours that are toxic and are also potentially flammable. Petrol, kerosene and diesel will spread quickly over the surface of the water and usually evaporate quickly.

Heavier fuels, most likely to be encountered at Marsden Pt or the Port Whangārei area, will not evaporate so easily. These types of oils will have to be treated with dispersants or collected in booms and skimmed into containers. Sometimes choppy water and whip an oil spill into what looks like a frothy chocolate mousse which is very difficult to dispose of because it floats so easily and forms large masses.

Responding to a spill

When the Northland Regional Council is told about an oil spill, the decision on how to deal with it depends on an assessment of the size of the spill, the type of oil involved and other conditions such as the weather at the time.

The health and safety of responders is of paramount importance in any oil spill response.

The regional on-scene commander of the emergency response team must decide if the resources of the NRC will be enough to deal with the spill, and if the costs will be less than $250,000. If the response needs resources costing more than this, it becomes a national scale emergency under the control of the Maritime New Zealand.

For larger spills there is sometimes a need to manage the response from a specially designated incident command centre.  The second floor of the NRC building has a purpose-built room set up for this purpose.  It is from here that the On-scene Commander assumes responsibility for coordinating the overall response for a large scale response. 

The On-scene Commander manages a team of specialist people who carry out a number of roles.  Their tasks include assessing information and determining areas for protection, preparing and implementing the best response options to deal with the oil, ensuring that the health and safety of the field teams are catered for, sourcing and purchasing additional equipment, manpower and provisions, notifying and updating the public and other interested parties on the response to date and keeping track of finances and administration.

So what are some of the common clean-up options used to minimise the effect the oil will have on the environment?  Well which option is best will largely depend on what has been spilt, how much is spilt and where it is spilt. 

Firstly, there is the do nothing option.  This is when it is decided that no clean-up is required and there is no deployment of equipment.  The slick is monitored and mother-nature is left to do her thing.  An example of this would be a small diesel slick that is left to disperse in choppy seas or left to evaporate in the hot sun.  If the slick was larger, and require some agitation to disperse it, then we might then put a boat on the water and use the propeller wash from the boat to break up the slick up a bit. 

In sheltered areas where there is an oil slick we might use pillows, booms and pads made of absorbent material or wool or sphagnum moss.  These items can be used to soak up the oil from the water.  This stuff is also great for spills into drains, streams and if we want to soak up oil floating around in the bilge water of boats. 

Oil spilling from a drain.Oil accidentally leaked into a drain by a local business poured out into Whangārei's Town Basin.Oil spill clean-up using absorbent materials.Absorbent materials were used to clean-up the oil that poured from the drain. 









For larger oil spills we may have to use large booms to contain or deflect an oil slick to stop it from going into a marina area or upstream into a mangrove forest.  Once the oil is contained we would then use skimmers and vacuum sucker trucks to remove the oil from the water.  Skimmers skim the oil from the surface of the water and are ideal to use when the oil is heavily concentrated.  The oil can then be transferred into a large floating tank and then the oil sucked out using a big pump on a truck parked on the wharf.

In Northland we have one of three self-propelled oil skimming recovery vessels.  The Taranui is kept down at Marsden Point and is ready to respond to a spill in the area within about one hour.

For other oil slicks it might be better to apply dispersants.  Dispersants are usually sprayed onto the surface of the oil slick from sprayer booms mounted out the side of vessels or it maybe manually applied from guys using backpack sprayers.  And for large slicks, dispersants would be applied on to the oil slick from a plane or a helicopter.  Dispersants are much like the detergents we use to wash our dishes.  Just as the detergent breaks down the grease and scum from off the plates when you are washing the dishes, dispersants break up the oil slick on to of the water by stopping the oil particles from sticking to each other.  Eventually the oil particles sink down into the water column where natural processes like biodegradation take place and the oil is eaten up by little greeblies in the water. 

If however the oil came ashore on a low energy beach for example then we may have to use graders and trucks to skim the surface of the beach to remove the oiled sand.  As you can imagine this is a costly exercise as large volumes of oiled sand and other debris would then sent to a specially designed landfill site down at Redvale near Albany, which is set up to take oily waste.

Cost recovery, Enforcement, Prosecution

Whenever possible, the full reasonable cost of any spill response and clean-up operation is sought from the person or organisation responsible for the spill. 

Therefore it is important that the response team maintain accurate records so that the cost of the operation/cleanup can be accurately and continuously assessed and recovered from the person responsible for the spill.  If the spiller can not be identified, then any response costs related to the clean up operation can be claimed back from the oil pollution fund via Maritime New Zealand. 

Following the cleanup of a spill, the Council may decide to either issue an infringement notice or to prosecute the person(s) responsible for spilling the oil.  This decision would take into consideration, the severity of the spill, the cleanup costs to date, whether the spill was intentional and how cooperative the spiller was in providing assistance.  Infringement notices carry a fine of up to $1000 and prosecution fines imposed by the court can be up to $200,000.  The cleanup costs are in addition to this.

So it is important to gather evidence throughout the operation for possible legal action.  This evidence can be witness statements, photographs and samples taken from the spilt oil and from vessels or other suspected sources of the spill.

Northland’s largest modern day incident

In 1999 a large oil spill occurred off the Northland coast between Tutukaka and the Poor Knights Islands. The oil reached the Poor Knights Islands Marine Reserve. The spill was bilge oil from a ship, and was spread over a wide area. Patches floated among the islands and clumps of black oil were found coating rocks. Once the council was alerted, a plane and a boat were chartered to investigate. The Council found there were limited options for cleaning up this spill. The waters around the islands were too deep to be able to anchor booms to contain the oil. Dispersants were also unable to be used because they would make the oil sink to the bottom of the sea – an unwanted outcome in one of New Zealand’s premier scuba diving areas. 

Cleaning oil off rocks using sorbent cloths.Cleaning up oil by hand using sorbent cloths is a messy business, as shown here at the Poor Knights Islands. Care is needed to avoid breathing fumes and skin contact. 






















Instead the oil spill response team had to scoop up what they could manually and use low pressure spraying of salt water to dislodge oil from rocks. The rest was mopped up by hand using sorbent cloths. The prevailing wind moved the slick away from the islands and the Northland coastline, averting a greater mess.

Removing oil from cave wall using salt water.Salt water is sprayed on at low pressure to dislodge oil from the walls of a cave at the Poor Knights Islands.












Why should you care? 

How big is the problem? About 23 million litres of used oil `disappears’ into our communities and back yards every year. Oil is often put in the rubbish, down the drain, painted on fences and used in chainsaws.

Just one litre of oil can contaminate 1 million litres of drinking water. The disposal of used oil is one of New Zealand’s major environmental problems.

How can you help?

Accidents do happen. Even the smallest spill needs to be dealt with promptly so that rain cannot wash it into the storm water system and out to a stream or beach or even into a water supply aquifer.

You can help by stopping the spill getting into a storm water grate and cleaning it up without causing water pollution. Block off access to storm water grates with covers, sandbags or absorbent material. Contain the spill with sand or sawdust, and sweep up solids or powders and put them in a safe container. Dispose of the waste appropriately at a landfill. If you are unsure how to deal with a spill, contact the NRC’s environmental hotline for advice.

Oil can also enter waterways through people cleaning barbecue plates into gutters and from pouring used oil into sinks and gutters.


What to do if you find an oil spill

Environmental hotline.Call the Northland Regional Council’s environmental hotline: 0800 504 639

The hotline operates 24 hours a day and seven days a week.

Do not touch the spill and be careful not to breathe any vapours as fuel is toxic. Do not touch any oiled birds or marine life without gloves as fuels and oils are bad for skin.