They were called to the 100 block of Starr Road in New Garden Township around 9:45 a.m. Thursday.
There were initial reports that some people were trapped inside. It's not yet known if firefighters found anyone.
A 2nd alarm was sounded shortly before 10:00 a.m.
The view from Chopper 6 HD showed heavy smoke billowing from the structure as firefighters worked to put out the flames.
There was no immediate word as to how this fire started.