A blaze about 7 p.m. in Emerson displaced a family.
BCFD Battalion Chief Bryan Keeling said the residents on Martin Luther King Jr. Street in Emerson were frying fish when the grease ignited.
The homeowners were unable to contain the blaze, which was limited to the kitchen and dining areas.
"There is extensive damage to the house. There is the smoke damage throughout the rest of the house," Keeling said.
A second blaze about 9 p.m. left the remainder of a vacant home a mass of burned debris.
Keeling said the structure on Pawnee Trail, a mobile home with a large addition built on, was under demolition and no one was supposed to be living in the residence.
Three engines and a ladder unit were dispatched to the fire, with firefighters extinguishing hot spots in the debris.
The cause of that fire is under investigation.
No one was injured in either blaze.