Oxford’s fire chief said a sprinkler system and quick reaction by firefighters kept a blaze at a manufactured homes factory from spreading significantly Friday night.

Chief Wayne Jones said the fire started in a stack of plywood in a corner of the Keiser Homes plant at 56 Mechanic Falls Road. He said the cause is unknown and the State Fire Marshal’s Office is investigating the fire.

Jones said the fire spread about 20 feet or so into the building. The sprinkler system kept the flames in check initially, he said, and firefighters were able to get water hoses set up quickly and started to spray down the building within minutes of arriving.

The fire was reported about 4:45 p.m., when most of the workers had finished for the day and only one employee was in the plant, he said.

One firefighter was taken to a local hospital to be treated for heat exhaustion, Jones said, and another was treated at the scene for what he said was a minor injury. No one else was hurt, the chief said.

Jones said even though firefighters were able to keep the flames from spreading, it still took about five hours to get the fire fully under control. He said an Oxford fire crew was expected to spend most of the night at the site to make sure there weren’t any hot spots remaining that could cause the fire to flare up.

More than a half-dozen nearby towns sent crews to help with the fire or to cover Oxford fire stations during the evening, Jones said.

Route 121, which is Mechanic Falls Road in Oxford, was shut down part of Friday evening but had reopened by about 10 p.m.