The Environmental Defence Society (EDS) has filed Declaration Proceedings in the Environment Court today (Monday) concerning the storage of ouvea premix at the former Mataura Paper Mill in Southland.

The Mataura sites on Kana Street were nearly inundated with floodwaters in February, sparking a civil defence emergency. 

The society contends New Zealand Aluminium Smelters Ltd (Tiwai Point aluminium smelter) is responsible for removing the hazardous substance but earlier this year the smelter's majority owner, Rio Tinto, vetoed an agreement between smelter and Gore District Council managers that the smelter would shift it.

The aluminium processing produces a byproduct called dross, which in a recycling process can be converted into ouvea premix.

If the premix gets wet, it can produce toxic ammonia gas, Environmental Defence Society chief executive Gary Taylor said in a media release today.

Ouvea premix has potential use in fertiliser manufacturing and steel production. 

“We are concerned that if the stored ouvea premix gets wet, it produces ammonia gas which is toxic to humans. It can also harm aquatic life. There are residences nearby as well as a Te Kohanga Reo child care centre,” Mr Taylor said.  

“It’s our contention that New Zealand Aluminium Smelters (NZAS) is responsible for the material and should be taking immediate steps to remove it promptly to a safe site,'' he said.

NZAS is owned by Rio Tinto (80%) and Sumitomo Chemical Company (20%).

“Rio Tinto does not have a good environmental track-record offshore, having recently destroyed a 45,000 year old Aboriginal cultural site in the Pilbara region in Western Australia. We wish to see a more responsible approach from NZAS to avoid adverse environmental impacts in this country,'' Mr Taylor said.

The backstory to the Mataura issue is complex. The ouvea has been on the site for several years.

NZAS had contracted out processing and recycling of the ouvea premix to a Bahrain-based company, Taha Asia Pacific, but it went into liquidation.

The liquidators eventually disclaimed premix, leaving the issue of clean up to territorial authorities and the Government.

The Environmental Defence Society contends New Zealand Aluminium Smelters is responsible for the premix at Mataura.

"Our Declaration Proceedings ask the Environment Court to rule on whether NZAS can contract itself out of legal responsibilities to avoid, remedy or mitigate adverse effects (or potential adverse effects) under the Resource Management Act.  

“The EDS proceedings are supported by affidavits that track the history of the matter and provide expert evidence on hydrology and chemistry. Our concern is that another flood event could inundate the warehouse storage facilities.  

“If the ouvea premix gets wet, it could release ammonia gas at concentrations that could harm people. Whilst such an event is a low probability, it could have serious consequences. The time frame for removal of the material, which is vague and uncertain, seems excessive given those risks,'' Mr Taylor said.