The Marshalltown Fire Department says a working smoke detector helped get two families out of their homes without early Friday morning.
Firefighters were called out to the 3200 block of South 12th Street around 3:00 a.m. on the report of two trailers on fire. When crews arrived, they found the flames had spread to a garage.
It took crews about four hours to extinguish the fires. None of the people living in either of the homes were injured.
The cost of the damage to the trailers and garage is estimated at $50,000.
The cause of the fire is under investigation.