Fire officials confirmed they were at the plant, one of the largest in the state. KCP&L, a unit of Missouri power company Great Plains Energy Inc, did not immediately respond to requests for a comment.

The Kansas City Star's website reported that heavy fire hit the first, second and third floors of the plant following an explosion, but all employees had been accounted for and there were no reports of injuries.

The plant's Iatan 1 unit has a 705-megawatt capacity and Iatan 2 has a capacity of 850-MW, according to the U.S. Energy Information Administration.

(Reporting By Scott DiSavino and Eileen Houlihan in New York; Editing by Maureen Bavdek)