UPDATE: CHATTANOOGA, TN (WRCB) Three Chattanooga firefighters were taken to the hospital - after a fire broke out in the piping system of a chemical processing plant, Wednesday.

Officials say a ruptured line started the fire and caused the chemical leak. All three firefighters were treated and released from the hospital. The plant's alarm system alerted fire crews, who responded in minutes. They were able to put the fire out quickly with the help of the built in sprinkler system. Officials say it was a close call -- the size of the fire and number of injuries could have been much worse..

For safety reasons, our camera was kept back as fire crews battled flames inside an open air chemical processing building, owned by NA Industries. The fire caused a release of the chemical --- Maleic Anhydride -- which the company uses in the process of making detergent and concrete additives. Firefighters came into contact with the chemical as soon as they got off the truck.

"They were not inside of the facility so they were not wearing their air packs at that time," said Chief Danny Hague, Chattanooga Fire Dept. "They were actually hooking up to the fire suppression system when the wind changed directions and they got the smoke and vapor that came back on them."

Tactical Services Chief Danny Hague tells us, the firefighters exposed to the smoke and vapor said they felt a burning- itchy sensation on their skin. Maleic Anhydride is considered to be a low hazard profile chemical, but exposure can cause skin and eye irritation. Inhalation causes coughing sneezing, throat discomfort and respiratory tract irritation. Fire officials say the department has responded to the plant before, but this is the first fire.

"There have been some in the past nothing for any kind of chemical fire... this is a first either in a long time or ever," said Chief Hague.

Sounding alarms prompted employees to call for help. In all 27 workers were evacuated from the scene. Officials say at least 4 employees stayed behind in a sealed safe room and shut off the valves that contained the leak. The buildings automatic sprinkler system helped them fight the blaze quickly. To be safe, Hazmat crews tested surrounding areas with an air quality monitor.

"We don't feel there is any threat or feel there was any product released off site," said Chief Hague.

N o employees were injured during the evacuation. Officials with NA industries declined to talk with us. The cause of the fire is still under investigation. Fire officials say the scene was turned back over to NA Industries who will now begin their cleanup up process. They too are conducting an investigation into what happened.

 Chattanooga firefighters who were transported to a nearby hospital after possible exposure from a fire and chemical leak are expected to be okay, according to CFD officials.

Danny Hague, Tactical Services Director for the Chattanooga Fire Department, tells Channel 3 that they got a call for a fire on the rack piping system in an open building at NA Industries Wednesday morning. 

A ruptured line at the plant's piping system started the fire and allowed the leak. The leak, was in a ruptured line carrying the chemical Maleic Anhydride.

27 people were evacuated to as four other employees stayed in a safe room to manage the plant during the incident. No employees were injured.

When the firefighters entered the building to fight the fire, they weren't wearing their breathing apparatus.

The fire was quickly contained.

Chattanooga Fire Department Haz-Mat teams are at the scene of an apparent chemical release at NA Industries at Riverport Road. The road is blocked off to allow responders to address the incident.

No plant employees were injured. Three firefighters were treated by Hamilton County EMS for inhalation and possible exposure at the scene.

Fire suppression systems were deployed.

NA Industries is a chemical plant that produces a variety of absorbent polymers, used in detergents and concrete. The company is a is a wholly owned subsidiary of Nippon Shokubai, Co. Ltd.