Deputies with Constable Mark Herman's Office said a large metal fan hit the firefighter in the bay of The Woodlands Fire Station 7.
The Woodlands Fire Department said Firefighter John Rigoni was performing routine checks on a fire truck when the station's overhead ventilation fan hit him.
SkyEye was above the fire station when Rigoni was flown to the hospital for serious injuries.
The fire department said, "The Woodlands Township is following established protocols related to employees injured while on shift."