Several Otago motorists suffered spluttering engines after buying petrol contaminated with water from BP and Mobil stations yesterday afternoon.
BP communications and external affairs manager Jonty Mills said the company became aware that 91-octane petrol tanks were contaminated at its Regent, Dunedin North and Oamaru BP sites about 5pm and 6pm.
The sites closed their 91-octane fuel tanks as soon as they were aware of the problem, but the stations remained open.
A "handful" of motorists who filled up at those stations had since reported having running problems and BP had helped some customers clean out their fuel systems.
The incident was found to have stemmed from the industry terminal in Dunedin, where it appeared some water got into a 91-octane storage tank, he said.
The terminal was a shared facility, used by BP and Mobil, and "a couple" of delivery trucks drew fuel from the affected tank at the terminal before the problem was discovered and the tank locked down.
An investigation into what happened was under way.
He said the situation was very unusual and BP was taking it seriously.
BP's engineering contractors, Fuelquip, were working on the tanks at the affected petrol stations.
"Water in the fuel is not a good thing," Mr Mills said.
The 91-octane tanks at the stations would need to be pumped out into another truck and refilled before they were reopened.
Any BP customers who filled up at the affected stations yesterday and believed they had a problem with their vehicle should call the BP helpline on 0800 800-027, Mr Mills said.
It is understood at least one Mobil station was also affected.
Mobil was unable to be contacted for comment last night.
