No flames were visible, and the employee said no one should have been inside the building on a Sunday night.
Firefighters busied themselves next to a pumper truck at 9:30 p.m., laying hoses and preparing a water holding tank.
Not knowing what might be on fire or how toxic it might be, they kept people including media personnel and employee Harvey Johnson from the building.
Johnson had showed up after getting a call from a relative who was listening to a police scanner.
Firefighters also kept a small group of bystanders away from the main gate, where three more trucks sat idling.
The plant employs nearly 100 people and builds overhead aerial work platforms.
Owners William K. Barefoot and William P. Fulton drove to the site, but did not return calls late Sunday.
In other fire news:
Later Sunday night, Redkey and Dunkirk firefighters responded to a fire at a pallet shop and warehouse at 10907 W. Jay County Road 600-S between Redkey and Dunkirk.
They later requested a pumper truck from Albany.
Police said no one was in the building, and no one had been injured.
Earlier Sunday, Muncie firefighters put out a fire at a house on the southwest corner of Mulberry and Fifteenth Streets owned by Jeff Buis. Buis said the laundry area in the five-room home was on fire when he came back from a trip to the Kmart and the library.
Neighbors called firefighters, who arrived shortly after Buis.
"I've owned the house for four years, and I paid it off last year," Buis said. "But I did not have insurance."
