More than 1,000 gallons of sulfuric acid has leaked into a containment area outside a nuclear plant in southwestern Michigan.

The Nuclear Regulatory Commission reports on its website that cleanup is ongoing Thursday at the Cook Nuclear Plant in Bridgman, southwest of Grand Rapids.

The agency says none of the acid was released into the environment or nearby drains. The leak was discovered Wednesday.

Plant spokesman Bill Schalk says a faulty gasket may be the cause and that a flange on a sulfuric acid tank's discharge valve was found leaking during a routine inspection.

The tank was holding 3,800 gallons of acid prior to the leak. The containment area is called a berm and has a reinforced concrete floor and concrete walls.