Northland Regional Council Maritime Officer James Harvey says the Marsden Pt oil refinery has been requested to carry out “comprehensive investigations” to discover the source of the spills, one of which may have involved up to 100 litres of a currently undetermined type of oil.
Mr Harvey says late on Saturday afternoon (January 22) Regional Council staff were alerted to the first of two oil spills - a slick several hundred metres upstream of the oil refinery jetty.
Investigations by Council staff confirmed oil stains on piles and vessels in the area – indicating a slick had indeed moved through the area - but no signs of oil upstream along the shoreline or the Northport wharf face.
However, about 8am Sunday, refinery staff contacted the Council to report a “reasonably large” patch of oil travelling down the harbour on the tide.
“It appears the slick had travelled up the harbour on the previous tide and was coming back down.”
A Council patrol boat was deployed to chase the slick and a small amount of dispersant was applied successfully to break up the roughly 20 square metre slick in the main shipping channel just south of Urquharts Bay. Samples of the oil were also taken.
Mr Harvey says about 11.30am refinery staff reported a new, second spill under the refinery jetty and a clean-up operation began that ultimately involved several Council and about 15 refinery staff.
Samples were taken and dispersant again used on heavier patches of oil to successfully break up about three-quarters of the spill, which may have involved up to 100 litres in total.
However, roughly a quarter of the spill had come ashore over a 600-metre long stretch of beach at the south-eastern end of the refinery, towards Mair Bank.
Refinery staff used a front-end loader to shift several tonnes of contaminated sand and shell above the high tide mark, from where it was to be removed today.
Mr Harvey says Department of Conservation, iwi and health officials were all alerted to the spill, “but fortunately the oil did not reach shellfish beds on Mair Bank, nor tuatua beds at Ruakaka Beach”.
A search of the area about 8pm yesterday revealed no further signs of oil.
“The refinery has been requested to carry out a comprehensive investigation into both incidents as soon as possible.”
Mr Harvey says the Council expects to receive preliminary findings from those inquires within the next day or two.
It was too early to say what enforcement action, if any, might be taken over the incidents, which were the first oil spills Council staff have responded to this year.