Centreport has finally confirmed that six cylinders containing the toxic fumigant methyl bromide were in the container that fell into Wellington Harbour during the July 21 earthquake.
The company said salvage experts retrieved the Kwikill container safely on Thursday, with the six 50-kilogram cylinders still intact inside.
The gas, also known as bromo-methane, is lethal and has been widely used on the waterfront for fumigating exported and imported products, particularly logs.
The container has now been shifted to a new home inside CentrePort's fenced-off fumigation area, about 50 metres from the waterfront. It was previously stored just metres from the water's edge.
Wellington Mayor Celia Wade-Brown said she was concerned that the cylinders had fallen into the harbour when a seawall gave way during the earthquake.
She was also concerned that the container had spent four days in the water before the retrieval operation was completed.
Greater Wellington Regional Council economic committee deputy chairman Paul Bruce said it was fortunate that the cylinders had not been damaged.
The Ministry of Business, Innovation and Employment said it was satisfied that the recovery of the container had been managed safely. "None of the cylinders were damaged, no-one was injured and there was no environmental damage . . . We would expect all workplaces, including the port, to review emergency management procedures, including where hazardous substances are stored, following the recent earthquake."
The main medical cause for concern about methyl bromide gas is a possible link with motor neuron disease. It has been linked to the high incidence of the disease among people working at and living near the Port of Nelson.
Six cases of the disease, a neurological condition that causes degeneration of certain brain and spinal-cord nerve cells, were recorded around the Port of Nelson between 2002 and 2005.
Kwikill owner Mike Hermansson said his company fumigated about 500 containers a year at CentrePort under instructions from the Ministry for Primary Industries. Another fumigation company, Genera, was responsible for the fumigation of logs on the Wellington waterfront.
Methyl bromide liquid gas cylinders were strong and, according to CentrePort chairman Warren Larsen, there were no concerns that their valves could rupture.
In June 2011, the Environmental Protection Authority gave local methyl bromide users 10 years to institute systems to recover all used gas. CentrePort indicated earlier this year that it would move to using methyl bromide gas recapture technology this financial year.
- The Dominion Post