It happened around 1:00 Saturday afternoon on the 300 block of West Summit Avenue in Elmhurst.
Dozens of firefighters worked to get the fast moving fire under control.
Neighbors say 36-year-old Nate Lewandowski ran out of the burning home but his eight pit bulls, including six puppies, were trapped.
"I looked outside the window and I saw this haze and just this smoke and it just looked odd because I couldn't even see across the street from my house. Then all of a sudden I heard a boom," said Victor Caruana, neighbor.
Lewandowski, who ran back in, was inside the home at the time of the explosion. It happened near the back of the house where the kitchen was located.
Investigators say first responders pulled him out and tried to revive him but he died at Christiana Hospital.
"It's just horrible, it's just unbelievable. We were shocked when we got the call from the fire marshal," said Ron Lewandowski, father.
Sadie, the mother of the puppies, escaped but she frantically ran around the yard. She even tried to go back in the house.
Her pups didn't make it and an adult male pit bull also didn't survive.
State fire marshal investigators spent hours gathering evidence from the scene.
"Our Major Incident Response Team is here. We are going to reconstruct the fire scene and hopefully pinpoint the origin of the fire, where it started and that will lead us to the cause," said Michael Chionchio, Delaware State Fire Marshal.
The victim's mother Maryellen and his adoptive father Ron say they bought the house for their son back in 1998.
He was quiet and kept to himself. They say his pets meant the world to him especially after he lost his 2-month-old daughter to SIDS three years ago.
Lewandowski had been out of work and was trying to straighten up his life.
"My wife is just devastated. He's our older son and we are going to have to tell our younger son and that's going to be very, very difficult to do," said Ron.
As the investigation into the cause continues, the victim's surviving dog Sadie is being cared for by a neighbor.