Just after noon on Sunday, witnesses said the fire was through the roof of the warehouse. Smoke was visible for miles.
Workers had been clearing the building this past week. NRG had not been manufacturing for several years.
Fire crews contained the fire to the warehouse, limiting damage to the manufacturing and office area.
Noblesville, Jackson Township, White River Fire Volunteers and the Cicero Fire Department all responded to work the fire.
A nearby apartment building 91 West Brinton was evacuated as a precaution due to heavy smoke.
Nobody was hurt.
The cause of the fire is still under investigation.