A small blaze that erupted in one of the cooling towers at the Palo Verde nuclear power plant Wednesday was quickly extinguished by firefighters, with limited damage to the unit, officials said Wednesday.

The largest nuclear power plant in the United States, the Palo Verde Nuclear Generating Station in Wintersburg, AZ, about 50 miles west of Phoenix, was the site of a small fire Wednesday.

Operator Arizona Public Service said in a statement that the fire broke out during scheduled maintenance work at the plant.

“During maintenance work on the Unit 3 cooling tower, grinding work began to cause a fiber glass shroud to smolder,” APS said. “A small fire developed but was quickly extinguished by the Palo Verde plant fire department.”

Firefighters were called out to the plant. Assistance from the Tonopah Fire Department ultimately proved unnecessary, as the fire was of small proportions and was quickly put out.

APS said the unit is currently out of service for refueling, maintenance and replacement of the steam generators.

Nobody was hurt during the incident and the damage was minimal.

The fiberglass shroud was the only material to suffer from the fire. Operations were not affected, officials said, and the unit's return to service will not be delayed, APS said. It is scheduled around Jan. 1.

The cooling tower for Unit 3 is located outside the station's fence and about a quarter mile away from the generating unit.

The plant is a major source of power for Phoenix and Southern California, and also serves homes in New Mexico and Texas.

Palo Verde has had troubles before.

In early November, the plant was shut down after security guards found what they believed to be a small pipe bomb in a worker’s truck entering the facility. Authorities concluded their investigations saying the pipe bomb would have been too small to cause any damage to the plant.

The worker, a 61-year-old man, said he had not been aware of the object’s presence in his truck and that it did not belong to him.