UPDATE: Efforts to ventilate the jail were complete after 9:30 p.m., according to a fire department news release.
The impact was isolated to the fifth and sixth floors, as well as part of the fourth.
"Hamilton County EMS evaluated all inmates in those areas. No injuries were reported," the release states.
Chief Deputy Austin Garrett with the Hamilton County Sheriff's Office thanked EMS and CFD for their quick work.
"We have no damage to the facility and no injuries. We are grateful for that. We worked together as a team to mitigate the smoke and do what needed to be done to ensure the safety of everyone in the facility," Garrett stated.
Officials are investigating the cause and origin of the smoke.
CFD Battalion Chief Ashley May said it was a major joint effort by all agencies involved.
The possible source of the smoke was isolated to the HVAC system, but investigators will determine the exact cause.
Several fire companies will remain on scene to assist in the investigation.
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UPDATE: Efforts to ventilate smoke in multiple areas of the Hamilton County Jail continued Tuesday evening in what the Chattanooga Fire Department called a "large scale joint operation."
What caused the smoke to flood areas of floors four, five and six remained under investigation, according to a fire department news release.
The fire department was called to the jail, located at 601 Walnut St., just after 6:30 p.m., and smoke was heavy upon firefighters' arrival.
Approximately 150 inmates had to be evacuated due to the smoke, according to Hamilton County Sheriff's Office Chief Deputy Austin Garrett.
"Extra security, EMS units and fire personnel were needed to handle the situation because of the size of the jail," the fire department release states.
Garrett added that no injuries and no damage to the building had been reported.
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ORIGINAL STORY: A malfunctioning heating, ventilation and air unit on Tuesday pushed smoke into the sixth, fifth and fourth floors of the Hamilton County Jail, necessitating the evacuation of some inmates.
There is no fire at the site, according to a news release from the Chattanooga Fire Department, but fire crews are ventilating the jail.
Some inmates were evacuated as a safety precaution, according to a tweet from the sheriff's office.