Firefighters in Carbon County battled flames inside a double block home.
It broke out around 2 a.m. Wednesday at 20 and 22 East Kline Street in Lansford.
Firefighters said both homes were vacant at the time of the fire, which apparently started in between both homes.
The building sustained mild to moderate damage.
Lansford Fire Chief Joe Greco said the fire did not appear suspicious, but is still under investigation.
Crews had the fire out in under 20 minutes.
No one was injured.