Chemical stored in Sawyers Bay, but ‘risk is minimal’

Explosive material stored near Dunedin has sparked concerns after the deadly explosion in Lebanon.

The company in charge of its storage says the risk is minimal, and it will be moved out of the site by the end of the year.

At least 137 people were killed and thousands more injured when 2750 tonnes of ammonium nitrate stored in a warehouse in Beirut exploded on Wednesday.

The chemical, used mainly for fertilising farmland, is also used as an explosive when mixed with a substance such as diesel fuel for bulk industrial operations in mining, quarrying and large-scale construction of bridges and roads.

An Otago Regional Council spokesman yesterday said it had been made aware of concerns about hazardous materials being stored in Sawyers Bay, and staff were looking into it.

RedBull Powder Company manages the storage and transportation of ammonium nitrate for OceanaGold’s Macraes mining operation.

Company general manager Chris Pilmer confirmed it stored ammonium nitrate in Sawyers Bay.

The company was permitted to store up to 1800 tonnes at the site, but the amount stored was "well under" capacity, Mr Pilmer said.

Its permit to store it there expires on December 31.

It expected to be out of the site before then, and new storage facilities at the mine were being constructed.

He said that the industry had learnt a lot from previous disasters involving the chemical, and the company did everything it could to ensure it was compliant with conditions at all times.

"Trust me, those conditions are very, very stringent," Mr Pilmer said.

Ammonium nitrate needed a large fire for it to explode, and would not combust on its own, he said.

A Ravensdown spokeswoman said it did not stock pure ammonium nitrate anywhere in New Zealand.

One of its products, CAN, has ammonium nitrate as an ingredient, and is classed as non-hazardous and non-flammable, she said.

New Zealand Fertiliser Quality Council member Anders Crofoot told RNZ yesterday ammonium nitrate was not commonly used here.

Urea is often used in New Zealand’s horticultural industry, rather than ammonium nitrate.

“[It] doesn’t have those same explosive characteristics.”

The Ministry for the Environment said there was no cause for concern over the controversial ouvea premix stored in Mataura’s old paper mill.

The ouvea premix did not contain ammonium nitrate, a spokeswoman said.

When wet it gives off ammonia gas, different from the ammonium nitrate which, if heated, gives off nitrogen oxides.