The operator of the Fitzpatrick Nuclear Power Plant says spilled lubrication oil that caused a sheen on Lake Ontario isn't hazardous and has low potential health effects.

The U.S. Coast Guard observed the sheen Sunday near the plant in Scriba, about 40 miles north of Syracuse.

An official from operator Entergy Corp. said Monday that the oil came from a tank that overfilled because of an equipment malfunction. A Nuclear Regulatory Commission spokesman said it appeared 20 to 30 gallons of oil entered the lake through a drain.

An NRC report says the reactor has been shut down since a loss of power to water pumps forced a manual shutdown Friday.