Georgia Power officials say employee errors led to an explosion that rocked Plant Bowen in northwest Georgia.

Georgia Power spokesman Mark Williams told the Atlanta Journal-Constitution Thursday that an internal investigation revealed employees at the coal-fired plant near Cartersville failed to comply with procedures and didn't follow communications protocols. The explosion happened as workers were shutting down a unit for maintenance.

Williams didn't elaborate on which specific protocols were breached, but says that led to the plant having a combustible mix of hydrogen and air in a generator.

The early April explosion left three people injured and prompted an investigation by the Occupational Safety and Health Administration. The federal investigation is not yet complete and no disciplinary action has been taken.

Tags: Georgia Power, explosion, coal-fired power plant, Plant Bowen