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Accident date
New Zealand
Accident area
Bay of Plenty, North Island
Spill area
Cause of spill
Quantity transported
Cargaison :1,368 containers (goods and various HNS including ferrosilicon and alkyl sulfonic acid) and 1,700 t of heavy fuel oil
Nature of pollutant
Fuel oil and containers
Ship / structure type
Container ship (Capacity: 3 500 TEU)
Built date
1990 (ex-Andaman Sea)
290 m
32 m
12 m
Costamare Shipping (Greece)
MSC (Mediterranean Shipping Company)
P&I Club
Swedish Club

The accident

In the early hours of the morning on 5 October 2011 (GMT), the Liberian-flagged container ship Rena, with a capacity of 3,500 TEU (47,230 DWT), grounded north of New Zealand, some twenty kilometres off the coast of Tauranga (specialised in wood export) with 1,368 containers onboard.
Since then, the vessel has been sitting on the Astrolabe Reef, an environment renowned for its flora and fauna (many colonies of dolphins, whales, seals and penguins).
To respond to the spill, shoreline and at sea response was placed under the authority of Maritime New Zealand.

As it happened, on 28 October, in the same region, a second grounding, thankfully without any major consequences, occurred. It involved the container ship Schelde Trader, which grounded at the entrance to Tauranga, shortly after leaving the port. No pollution was reported.



Nature of the cargo

The risk of pollution was generated both by the bunker fuel and the cargo within the containers.  
The 1,700 tonnes of oil (heavy fuel oil and engine oil) were on board at the time of the incident and were at risk of being released into the Bay of Plenty, one of the country’s most popular tourist destinations.
The container ship Rena was carrying 1,368 containers, including 32 containing hazardous substances and 121 containing perishable foodstuffs. 547 of them were on deck and 821 below deck.
In total, an estimated 169 containers fell overboard.

53 of these lost containers were identified: one of them contained hazardous substances (including alkyl sulfonic acid, UN 2586). 23 containers washed up on the shore. The search for missing containers is still underway.


Potentially hazardous substances transported


UN number

Ferrosilicon (500 t)


Alkyl sulfonic acid (23 t)


Hydrogen peroxide (40 t)


Potassium nitrate (24 t)


Trichloroisocyanuric acid (5.4 t)


Response operations at sea

On 6 October, the first slicks were observed. The starboard tank was pierced and pollutant was leaking out. The company Svitzer was contracted to conduct wreck treatment operations.

The day after the incident, dispersant spraying operations began on a 5 km-long oil slick, around the ship. However, these dispersants proved to be inefficient on this pollutant. Meanwhile, stocks of booms and other equipment arrived on site to be deployed so as to protect sensitive sites.
Maritime New Zealand (MNZ) declared the accident a Tier 3 emergency, the highest level of pollution risk. An Incident Coordination Centre (ICC), composed of 200 people, was set up in Tauranga.
Offers of national and international assistance came flooding in, with experts arriving from the UK, Australia and Singapore from 8 October to provide technical advice.
New Zealand Defence Force personnel and vessels arrived on site on 9 October 2011 to back up Maritime New Zealand teams.
Pollutant recovery operations began at sea on 9 October, but proved to be of limited efficiency. The pollutant (IFO 350) rapidly became very viscous, due to the temperature conditions on site.
On 10 October, New Zealand’s Prime Minister took part in an overflight and declared that the reason for the grounding was unknown, given the calm weather conditions at the time of the accident.
The Rena’s captain was arrested on 12th, and his second officer the following day, charged with “operating a vessel in a manner causing unnecessary danger or risk”.

Oil pumping and container recovery operations

Onboard the vessel, salvage teams in charge of pumping the fuel out of the vessel’s tanks had to inject water and use booster pumps to remove the viscous fuel oil. The recovered fuel was transferred to a barge located 100 metres from the Rena.
On 13 November 2011, oil pumping operations were completed, with a total of 319 tonnes collected. Only 60 tonnes remained in the number 5 starboard tank, to be pumped out during the container removal phase.

The second response phase began on 16 November with the removal of the first container from the rear deck using the crane barge Sea Tow 60. This proved to be a very tricky operation. Experts estimated that 6 containers could be removed per day. If 1,280 containers remain onboard, this means that the operation should take over 7 months. The containers have been equipped with locater beacons (called ‘pingers’) so that they can be easily detected if they fall overboard.
In total, 1,007 containers were recovered. Of the 1,700 tonnes of fuel oil initially on board, an estimated 200 to 300 tonnes was spilt at sea.

Wreck management

Meanwhile, a salvage plan was prepared by Svitzer's Dutch naval architects, based on the ship’s resistance calculations. Motion sensors have been fitted to the vessel to monitor its stability and measure hull movements.
On 10 October, a storm made response operations very difficult and caused a large crack to form on the port side of the vessel. The hull was at risk of breaking in two. The vessel was listing heavily (22° starboard list), and the crew were evacuated.
Several weeks later, due to adverse weather conditions on site, the Rena cracked and partially broke in two on 1st January 2012. Initially, the two parts appeared to still be joined at the bottom of the hull. Sensors were rapidly installed to check the vessel’s structural stability. The wreck’s situation remained stable for a week, during which container removal operations continued.
Finally, the Rena broke completely in two on 8 January. The bow section remained firmly on the reef while the stern drifted about 30 metres away before finally sinking.
300 of the 800 containers remaining onboard at the time fell overboard. They contained, among other things, powdered milk and timber.
A 3 nautical mile exclusion zone is in place around the wreck due to the high collision risk caused by the presence of containers and debris at sea.
The oil pollution risk remained present with around 350 tonnes of fuel oil remaining in the Rena’s tanks, and a new aerial surveillance campaign was set up.
During wreck dismantling operations in September 2012, 430 tonnes of steel from the bow were evacuated by helicopter.
Operations to cut up the submerged part of the vessel by 2 teams of divers began in the following weeks.

Response operations on land

From 7 October, clean-up and wildlife rescue teams conducted shoreline assessments to determine the sites to be protected, identify priority areas for clean-up in the event of pollutant arrivals and define the techniques to be used. Booms were deployed to protect sensitive shoreline areas.
Following the storm on 10 October, the first arrivals of oil were discovered on Mt Maunganui beach. Clean-up teams immediately took action. On land, beaches were closed from Mt Maunganui to Maketu Point.
By the 14th, 60 km of coastline had been polluted.
Environment Minister Nick Smith described the grounding as New Zealand’s “most significant maritime environmental disaster”. This situation was all the more detrimental at a time when New Zealand was in the international spotlight as it hosted the Rugby World Cup.

Overview on 12/10/2012

Tonnes of fuel pumped out

1 300

Number of containers recovered

1 007

Tonnes of waste collected on the beaches

1 041

Number of volunteers registered

8 061

Number of dead birds collected

2 410

Management of volunteers

On 12th October 2011, an official call for volunteers was launched online via the "Adopt a beach" programme, in close collaboration with the Pākehā and Māori communities. 
The volunteers called upon for clean-up operations were mainly between 30 and 60 years old. Some people even took time off work to help with the clean-up.
An online database was set up, via which some 8000 volunteers registered. Up to 1000 volunteers were involved in operations each day. Messages were sent out to volunteers by email, text message and via social media on a daily basis. A debrief was systematically undertaken with volunteers before they left the beaches. 
To thank volunteers for their involvement, they were invited to meals and concerts. Gift vouchers were also handed out.

Environmental impact

The Bay of Plenty is one of the most popular tourist sites in New Zealand. It is also home to dolphins, whales, seals, penguins (in particular blue penguins) and various seabirds…
Oiled wildlife was sent to a national wildlife centre, were over 400 animals were cared for. By 22 November, the number of dead birds had reached the 2,000 mark.
Scientific studies on the impact of the Rena pollution and in particular the impact of dispersants on wildlife are currently underway.

International cooperation – action by Cedre

An engineer from Cedre was sent to New Zealand from 22 to 30 October, upon invitation by Maritime New Zealand, in an observatory and advisory capacity on the incident management.
The on site engineer was able to take part in SCAT surveys and to visit waste treatment sites and a wildlife care centre.


MSC, the Rena's charterer, made a NZ$1 million “voluntary donation” (approx. €570,000), and the Swedish P&I Club which insures Costamare indicated that it intended to cover all costs related to the incident, including those related to pollution.
The enquiry showed that, under pressure to reach the Port of Tauranga before the tidal window closed to enter the port, the captain ordered a shortcut to be taken, causing the Rena to run aground on the Astrolabe Reef.
In May 2012, the captain and navigation officer of the Rena pleaded guilty to operating a ship in a dangerous manner, releasing toxic substances, and attempting to pervert the course of justice (falsifying documents). They were sentenced to 7 months imprisonment.
The owner was fined NZ$300,000 (approx. €190,000) for having released hazardous substances and an additional NZ$10,000 (approx. €6,400) for every day the pollution continues.

Similar grounding incidents




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Last update on 01/04/2014

See also

Sea & Shore Technical Newsletter, 2015, n°41

Sea & Shore Technical Newsletter, 2013, n°37

Sea & Shore Technical Newsletter, 2012, n°35

Sea & Shore Technical Newsletter, 2011, n° 34

Cedre Newsletter: Monthly instalments on the Rena pollution in the Cedre Newsletter from n°195

External links

Maritime New Zealand, Authorities in charge of response. Information on all aspects of pollution response at sea and on the shoreline. Daily updates on operations.

Independent Review of MNZ’s response to the grounding of the Rena, Report of the Independent Review of Maritime New Zealand’s Response to the MV Rena Incident carried out by former Secretary of Foreign Affairs and Trade Simon Murdoch.

Bay of Plenty Regional Council, Information on all aspects of shoreline response to the Rena incident.

Svitzer, Company contracted to deal with the wreck of the Rena.

Forest & bird, Information on the impact on birdlife.

AMSA Oil Spill Monitoring Handbook, Handbook by the Australian Maritime Safety Authority and Maritime New Zealand providing guidelines for undertaking monitoring for actual or potential marine spill responses.

Report of the TAIC (Transport Accident Investigation Commission) Full report.

CIIMAR database:  fate and weathering of Hazardous and Noxious Substances (HNS) involved.

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