South Bend, IN – Fire officials along with NIPSCO are trying to figure out what caused a house explosion in northern St. Joseph County.

It happened around 8:15 Thursday night in the 22000 block of Arbor Pointe Drive near Portage Road.

The explosion was so intense that the home was leveled and windows on nearby houses were blown out.

66 year old John Floyd, the man who lives in the house, suffered critical injuries.

He was taken to Bronson Burn Center in Kalamazoo.

We’re told he has three kids and several grandkids.

NIPSCO checked the gas supply lines overnight and found flow problems.

Now Clay Fire Officials are focusing on the inside of the house, in the basement where the explosion started.

Clay Fire Territory Marshal Dave Cherrone says, “In this case we’re looking at some natural gas fueled appliances and their optimum level of ignition.”

Cherrone says anything could’ve triggered the blast, even something as simple as turning on a light switch.

We’re told officials will put up a 6 foot high fence around the site of the explosion as they continue to investigate.