An urgent safety assessment of Lyttelton Port's fuel tanks starts tomorrow but it is unclear how long it will take, leaving those nearby anxious for answers.
The risk to homes in the event of a major disaster was identified by Z Energy, alongside BP and Mobil, as part of a submission on the Canterbury Regional Council's draft Lyttelton Port Recovery Plan.
The threat has cast doubt on plans to build a cruise ship terminal nearby and raised questions about whether the overall risk to residents has ever been assessed.
A report by an independent panel reviewing the port's recovery plan has recommended the city council urgently undertake a full risk assessment of the harbour's oil storage facility.
It said the submission from the oil industry, which outlines a potential 250-metre exclusion zone, has created uncertainty about whether a cruise ship terminal could be developed at Naval Point.
Terminal operations manager at Z Energy, Danusia Wypych said the company's own assessments did not look at the potential threat to nearby homes, in the event of a fire or explosion.
"We have operational risk assessments, but not one that looks at the interactive nature of the uses around the land."
Danusia Wypych said a quantitative risk assessment would be much broader and would also assess which products were stored in which areas in the port.
She said Z Energy had a range of concerns about the development of a cruise ship terminal, in the absence of a full risk assessment.
They included a large number of bus or truck movements in the area, accessibility, increasing the number of people near the tank farm and the ability to respond to a major event.
It remains unclear whether a full risk assessment of the facility has ever been conducted.
A spokesman for Z Energy said the oil industry called for a full risk profile of the storage facility in 2008, when a residential development at Naval Point was proposed, but said the assessment was never done.
The Lyttelton Port Company and the regional council said they were not aware of such a request.
A regional council spokeswoman said the onus to conduct a full risk assessment would probably fall on the city council.
The council did not respond to an enquiry yesterday about whether a full risk assessment had ever been conducted.
Chairwoman of the Lyttelton Information and Resource Centre Trust Wendy Everingham said many residents did not support the Naval Point site for the cruise ship terminal.
"It's located right out near the oil tanks, it's quite desolate out there and it's not connected to the township properly."
She said the trust's preferred location was at Gladstone Quay, in the inner harbour.
She said there had always been concerns about the proximity of homes to the tank farm, especially after a landslip damaged one of the tanks, which resulted in about 1500 litres of fuel leaked into the harbour in March last year.
Kirsten Disse, who owns a house nearby, said the onus was on the oil companies to ensure their tanks were safe.
"I'd like to see them built to a safe standard. If it was found to be really dangerous that would be bad for us and the value of our house."
The council will begin work on the risk assessment tomorrow.