A large fuel fire broke out at a KeySpan power plant in Port Jefferson Wednesday evening.

The county fire marshal and Town of Brookhaven firefighters were at the scene to determine the exact cause of the fire. KeySpan says the fire started in a boiler room on the ground floor before 5 p.m. when a gasket on a pipe that brings oil into the plant broke.

Oil was released into the air and ignited, KeySpan says. Employees were in the boiler room when the fire broke out, the company says, but they were not able to extinguish the flames.

Authorities said the fire was contained within the Beech Street plant and presented no threat to public safety. An environmental team was also on the scene to determine if any damage was caused by the fire.