The NZ Refining Company is investigating the source of a suspected gas leak which forced the evacuation of more than 400 pupils from Bream Bay College in Whangarei yesterday.
It was thought the gas leaked from a ship at the NZ Refining Company jetty.
Acting refinery general manager Shaun Dyke said thegas which sparked the school evacuation had a "light-oily, lpg" type of smell and appeared to have come from one of two overseas tankers berthed at the refinery.
The two vessels were the British Success, a crude oil tanker, and the Bright Express, a product tanker.
The British Success had been discharging crude oil at the time and the Bright Express discharging a gasoline component.
Mr Dyke said refinery staff had first noticed a smell similar to natural gas at about 2.30pm and begun their own internal checks.
However, at about 2.50 pm Bream Bay College had contacted the refinery to say it had evacuated its classrooms because of the smell.
No one - either at the school or the refinery - had required any medical treatment and no refinery equipment had been shut down.
Mr Dyke said refinery, Fire Service and Northland Regional Council staff had all responded to the incident.
A thorough investigation was being carried out, but it appeared the incident had not posed any danger.
