Rio Tinto’s liability for smelter site unclear

The Ministry for the Environment says it is unclear whether Rio Tinto is under any legal obligation to remediate the site of its aluminium smelter at Tiwai Point after it closes.

The Rio Tinto-owned smelter company, New Zealand Aluminium Smelters (NZAS), says it is conducting an extensive closure study to understand any environmental impacts on the Tiwai site and to ensure the operation will be closed in a responsible manner.

In January, NZAS announced the site would stay open for four more years, after it announced in July last year it would close in August 2021.

Ministry chief executive Vicky Robertson told Parliament’s environment select committee on Thursday that the legal liability for Rio Tinto to remediate the site once the smelter closed had been ‘‘difficult to pin down’’.

Robertson was being questioned at an annual review of the Ministry for the Environment and the Climate Change Commission.

Select committee chairwoman Eugenie Sage said there had been media coverage that a previous government had wiped any liability of Rio Tinto for the remediation of the site.

She asked Robertson whether that was the ministry’s understanding.

Robertson said there were ‘‘still tensions about Tiwai’s remediation of the site generally’’.

‘‘We are in ongoing conversations with them about remediation, and I’m pleased to say that remediation is part of the conversation about whether Rio Tinto stays or not . . . It’s definitely a strong part of what is required of them should they leave.

‘‘The difficulty is the amount they are liable for. The quantum has always been the issue.’’

Labour MP Duncan Webb asked whether it was accepted that Rio Tinto was liable for the remediation of the site both contractually and under the appropriate regulations.

Robertson replied: ‘‘I think it’s a little less clear legally.’’

Webb asked whether that meant ‘‘contractually or . . . is that because of the contracts that have been entered into, or because of arrangements with government, or because of the law as it stands?’’

Robertson replied: ‘‘In terms of the legal liability, that has been difficult to pin down.’’

An NZAS spokesperson said it took its operating responsibilities seriously and in accordance with all relevant legal and regulatory requirements.

The spokesperson said the company’s closure study process was a lengthy one, involving the expertise of several independent environmental scientists.

‘‘The first phase of this study is due to be completed late this year and includes extensive consultation with officials, our local community and Nga¯ i Tahu as mana whenua.’’