The incident happened around 7pm Thursday just outside Station 31, which is located on West Crosstimbers near Old Yale.
Houston Fire Department spokesman Ruy Lozano says one of its ladder trucks was pulling out of the station to turn eastbound on West Crosstimbers when it struck a pedestrian, who investigators say is a man in his 30s, walking on or near the sidewalk.
Fire department officials say the truck had its lights and sirens on, and firefighters jumped out of the truck to help the victim.
The agency would not provide any more details, saying it doesn't want to compromise the integrity of a Houston Police Department investigation.
"This is a very troubling time at the Houston Fire Department. The members are very upset," Lozano said. "Our thoughts and prayers really go out to the victim and the victim's family."
The man was transported to a nearby hospital and is listed as stable.
Crisis counselors were dispatched to talk to the firefighters who were at the fire station.
Detectives say it's still too early in their investigation to comment on whether the fire truck's driver may have done anything wrong.
This isn't the first time a Houston Fire Department fire truck has been involved in an auto-pedestrian accident.
In 2009, a woman riding her bike was killed after two fire trucks collided at an intersection in the Montrose area. The driver of one of the trucks was issued a citation but no criminal charges were filed.