Residents reported seeing a large fire light up the night sky in West Oahu Thursday following a malfunction at the oil refinery in Kalaeloa.
Par Hawaii Refining officials said there was an unplanned shutdown in one of the units at around 9 p.m.
As a safety measure, workers are trained to burn off material to depressurize the facility.
A spokesperson from the company says the cause of the shutdown is unclear.
Resident reported seeing the sky light up as far away as Mililani.
Par Hawaii is one of the largest oil refineries in the state. It has the capacity to handle 94,000 barrels of crude oil per day. The oil is then distributed to Hele, 76 gas stations and to other parts of the state.