The bill for cleaning up toxic waste lying beneath Auckland's proposed waterfront development is estimated at somewhere between $20 million to $40 million - and there's a high chance ratepayers will foot some of it.
Despite decades of concern over contamination on the Tank Farm and a court case, no one can say how bad the contamination is or how much it will cost to fix.
Ports of Auckland has estimated the cost at somewhere between 5 per cent and 10 per cent of the public infrastructure costs, which are estimated at $400 million.
Auckland Regional Council, the environmental regulator for the site, Auckland City Council and Ports of Auckland have ordered an investigation of the contamination, at a cost of $160,000, with help from the Environment Ministry. The results won't be known until next month.
Ports of Auckland owns the 18ha that is not in private ownership on the 35ha site. Ports is 100 per cent publicly owned by Auckland Regional Holdings, the ARC's investment arm.
"The liability issues are complex," said ARC councillor and strategy and planning committee chairman Paul Walbran.
"I can't tell you how much it's going to cost and no one at this stage will put up their hand to say who's going to pay because they all say it's the other guy."
Petro-chemical storage spills over decades have caused hydrocarbon contamination on the site but fill used for reclamation from the early 1900s included waste from an old gasworks, incinerator waste and demolition materials.
The soil is contaminated up to 2m deep, toxins leach to groundwater and into the harbour and disturbance might make things much worse.
In a clean-up operation, the contaminated soil may have to be dug up, taken by truck to a landfill and replaced by clean soil.
The nearby Beaumont residential development, which sits on contaminated land, was built using a vapour cover, said ARC contaminated sites manager Sarah Pinkerton.
"It depends on the level of contamination what will be required," she said, "but we are talking millions. It won't be cheap."
The developer paid for remediation at Beaumont St.
Ports of Auckland has already mounted a legal case over the Tank Farm against BP over how big a cleanup the oil company needed to do on a 2ha site it was vacating. In 2003 the High Court ruled that BP was not required to clean up contamination that occurred before 1994 and that it only needed to remediate the site to its industrial zoning use.
Aucklanders can have their say on the rules for the Tank Farm by sending views to the Auckland City Council by March 17.
To get a form call the council on (09) 379-2020 or visit www.aucklandcity.govt.nz