An investigation continues into the cause of a propane leak that caused an explosion at a home in Oakland on Thanksgiving.

According to the Portland Press Herald, homeowner Cliff Hannon remained in critical condition in the hospital in Portland on Thursday.

Oakland’s fire chief says there were four propane gas appliances in the house, with the fire marshal and insurance company working to determine which one may have had a malfunction or a leak.

Two neighboring homes were also damaged by the blast, displacing both families.