Environment Minister David Parker says he has had enough of Rio Tinto and is considering legal action against the owner of the Tiwai Point aluminium smelter over its failure to deal with its hazardous waste.
Parker's tough words follow claims the company reneged on a verbal agreement given last week to remove the waste that has been stored in the Southland town of Mataura for the past six years.
The 10,000 tonnes of ouvea premix in a disused paper mill came close to being inundated by floodwaters last week which could have set off a highly dangerous cloud of ammonia gas.
Rio Tinto's website states it is committed to mitigating its operations' impact and has stories about its efforts to help look after the environment, from bears in Canada to native trees in Australia.
Parker said Rio Tinto needed to clean up its "mess" in Southland.
"For them to try and escape some responsibility for cleaning up the mess that comes from their own smelter. It's outrageous. I can't reconcile it with these statements of corporate responsibility that they put on their own website.
"You know, they talk about preserving grizzly bears in Canada and migrating birds in Australia. Well perhaps they could take the same stance when it comes to the people and the environment of Southland."
Rio Tinto thought it had dealt with the problem when it paid Bahrain's Taha Industries to take the dross off its hands in 2014.
That company went into liquidation in 2016 and the waste sat in the old paper mill until a deal was cut last year between the government and local councils to move it over six years.
Fast forward to last week and a verbal agreement Gore District Council chief executive Steve Parry said he made with the chief executive of the smelter, Stewart Hamilton, sealed with a handshake, to remove the dross and store it at the smelter.
Parry said the head of the smelter had now reneged on that deal.
David Parker said that was disgraceful.
"Central government agreed to kick in a million dollars, the smelter a bit more than a million dollars and the councils some hundreds of thousands of dollars to get the clean-up started in a major way.
"You know, we didn't bring to bear those underlying legal liability issues but, you know, maybe we the government should be looking at suing them now. I've had enough."
Smelter chief executive Stewart Hamilton did not return RNZ's calls asking for comment. He released a statement which did not address whether the company had given a verbal undertaking.
The statement said the company remained "committed to a solution" and to contributing to at least some of the cost of removing its own waste.
Sort Out The Dross action group spokesperson Cherie Chapman said Rio Tinto should take care of its waste instead of palming off the problem on to the people of Southland.
"The community is very angry, very concerned, very bewildered about why this stuff has not been picked up at speed and taken out of the end of the Mataura paper mill."
Chapman said it was important to remember that nobody in Mataura had a say about the dross being stored in the middle of their town.
"It was snuck in to those buildings without any consents whatsoever, and the resource consent was then retrospective. Shortly after the company went into liquidation. The council has no recourse really when a company goes into liquidation, this is why I think Rio Tinto needs to pick up its act."
Chapman was sending out an open invitation to the smelter to attend a public meeting in Mataura on Friday night to discuss the problem and what should be done about it.