Heavy smoke and flames greeted Saskatoon Fire crews as they responded to a blaze in the Forest Grove neighbourhood Wednesday afternoon.
They arrived at the trailer on Grant Street around 3:30 p.m. and immediately called for reinforcements.
According to crews the fire spread to a nearby building but was quickly brought under control.
M.D. Ambulance was called to the scene to assess two 50-year-old men. One was released right away, but the other was taken to Royal University Hospital in serious condition.
A fire investigator is looking into the cause.