Channel 3 is learning more about Tuesday night's response to a fire at the Watts Bar Nuclear Plant in Spring City.

A failed transformer started the fire, and prompted what is called an "unusual event" emergency. That is the least significant of the Nuclear Regulatory Commission's emergency classification levels.

Crews on site were able to put out the fire, but local agencies were called for backup. Volunteer firefighters go through yearly training at the plant to stay prepared for emergencies.

"It's like any other plant that may have an emergency," said Tony Finnell, Meigs Co. EMA Director. 'Our objective is to try to take care of the emergency as quickly as possible."

Emergency crews were ready for the worst on Tuesday night, when a fire was reported at the Watts Bar Nuclear Plant.

TVA Spokesperson Jim Hopson confirmed that flames broke out in the plant's switch yard.

"The switch yard is part of the transmission system, not part of the nuclear generation or power generation system at the plant," Hopson said. "It was not involving the reactor, or any part of the plant proper whatsoever."

Emergency crews on site were able to extinguish the fire without any injuries.

READ MORE | UPDATE: Failed transformer causes fire at Watts Bar Nuclear Plant

As a safety precaution, TVA called for backup from local agencies. Four Rhea County fire engines responded to the plant, while Meigs County firefighters remained on standby.

"Just because it involves radiation, does not always mean we're fixing to face a hazard with radiation," said Finnell, "but we always have to keep that in the back of our minds."

Even though Tuesday night's fire was not a big emergency, local crews -- all volunteers -- are ready to respond to the worst, to keep their surrounding communities safe.

"There's little to no pay for what we do," Finnell said. "At the same time, it's just the love for the job."

Investigators are working to figure out what caused the transformer fire. The Nuclear Regulatory Commission is also looking into the incident.