Investigators said a fire that destroyed multiple businesses in a Sunnyside truck complex last month appears to have started from a dog kennel heater outside one of the buildings. Fire crews initially thought the January 13 blaze at 181 Factory Road was ignited by a propane tank. One firefighter injured his hand and a dog died in the fire. Three businesses in the truck complex sustained damage estimated to be about $500,000. Investigators said the flames intensified because of nearby propane and other fuel tanks.