The Callaway Energy Center owned by Ameren Missouri will shut down the nuclear reactor at the facility next week to start the plant's normal refueling process.
Some contract workers at the plant were injured Tuesday during what Ameren Missouri is describing as an "electrical flash" in a switchyard located about 300 yards from the nuclear reactor.
The shutdown of the plant was scheduled before Tuesday's accident at the plant. The injured workers were employed by another firm hired by Ameren working at the plant prior to the normal shutdown for refueling and maintenance.
Ameren Missouri announced Thursday a fourth person was injured in the incident. Three of them announced previously were injured directly by the electrical flash.
In a statement released Thursday afternoon, Ameren Missouri reported the fourth person was injured while attempting to assist the three others impacted by the flash.