It happened early Monday morning in Merrillville.
A 37-year-old male resident died in the explosion. The house was leveled.
Emergency crews pulled several propane tanks and gas cans from the wreckage.
Officials have evacuated residents in a two-block radius until 5 o'clock Tuesday night over fears of a hazmat situation.
"Gasoline was detected in the sewer system and in the homes. And so we had to evacuate the residents in the area and conduct a search of all the homes and check the levels, which we found explosive levels in the house, in multiple houses," said Michael Sneiderwine, Ross Township Fire Service.
No other injuries have been reported and investigators are trying to determine what sparked the explosion.