A routine maintenance outage went awry at Southern Company's (NYSE:SO) coal-fired Plant Bowen on Thursday. According to the utility, an explosion occurred at one of the plant's four units "the cause of which is still under investigation."

Southern reports that no employees were seriously injured and that the explosion does not present a threat to the local community.

The Cartersville, Ga., plant has a generating capacity of 3,160 MW and, according to a 2007 Southern report, was the second-largest generating plant in the Western Hemisphere at the time.

With a total generating capacity of approximately 43,000 MW, Plant Bowen's current outage represents a 7.3% drop in Southern's total capacity. All four of the plant's units are currently offline, but customers will continue to receive electricity via company contingency plans. A previous unplanned outage at Plant Bowen also caused the utility to miss on a key performance efficiency target for fiscal 2012.