The Yakima Fire Department says they responded to three fires in less than seven hours overnight.
YFD says the fires began Wednesday night through March 26, Thursday morning.
For the first case, the fire district says they were called to the 700 block of South 6th Street at 9:00 p.m for a propane explosion in a recreational vehicle.
YFD says two men inside suffered 2nd degree burns and were transported to a local hospital in stable condition.
Fire crews say the cause of the fire was determined to be accidental.
Before midnight, YFD was called about another fire incident located at the 900 block of North 4th Street for an exterior fire involving a commercial building.
The fire district says they contained the fire to a heating, ventilation and air conditioning unit.
YFD says there were no injuries, but the estimated dollar loss was $10,000.
Fire crews believe the fire was intentionally set.