October 27, 2008

Quad Cities Station Declares Unusual Event

CORDOVA, Ill., Oct. 27 /PRNewswire/ -- Operators at the Quad Cities Generating Station declared an "unusual event" at 3:03 a.m., after a gas explosion occurred inside the vestibule of an outbuilding near the plant early this morning.

Both Quad Cities units continue to operate at full power. The outbuilding, about 100 yards from the power generating portion of the plant, houses a rarely used tank and pump for storing floor drainage from the plant.

There were no injuries to plant personnel, no damage to equipment and at no time was there any concern for the health and safety of the public. There was no radiological release.

Plant operators are investigating the cause of the event.

Exelon Nuclear personnel notified all appropriate federal, state and local government officials of the unusual event, the lowest of four emergency classifications as defined by the Nuclear Regulatory Commission.

Quad Cities Generating Station is located in Rock Island County, five miles north of Cordova, Ill. With both units at full power, the station can produce more than 1,700 net megawatts of electricity, which is enough to power nearly two million homes.

Exelon Corporation is one of the nation's largest electric utilities with approximately $19 billion in annual revenues. The company has one of the industry's largest portfolios of electricity generation capacity, with a nationwide reach and strong positions in the Midwest and Mid-Atlantic. Exelon distributes electricity to approximately 5.4 million customers in northern Illinois and Pennsylvania and natural gas to approximately 480,000 customers in the Philadelphia area. Exelon is headquartered in Chicago and trades on the NYSE under the ticker EXC.

Exelon Nuclear

CONTACT: Krista Lopykinski of Exelon Nuclear, +1-630-657-3602

Web site: http://www.exeloncorp.com/