Firefighters responded to an 8:32 a.m. report that an onion-dehydrating machine was potentially burning at Gilroy Foods on 1350 Pacheco Pass Highway, Gilroy Battalion Chief Ed Bozzo said.
Responding firefighters found fires inside machines they opened, including the inside of an onion-dehydrating machine that was about 300 feet long, Bozzo said.
"It's kind of like an oven. A long oven," he said.
Crews scoured the factory's ducts and pipes, which had smoldering products from the machine fires.
The fire created an extensive amount of smoke, and after much exposure, one firefighter was taken to the hospital as a health precaution.
But the fire itself never became too active, Bozzo said.
"It was mostly contained to the machines," he said.
Firefighters finished controlling the fire at about 12:55 p.m. A damage estimate was not immediately available.