Neighbours to the home in Agassiz (agg-ah-see) say they heard a loud explosion followed by several smaller blasts just before 7 p.m. on Sunday.
Agassiz Deputy Fire Chief Gerald Basten says crews arrived when the house was fully engulfed in flames.
He says two people, both adults, managed to escape and get to a neighbour's house, but suffered serious burns to most of their bodies.
Basten says one person was airlifted to a Lower Mainland burn unit, and the other was rushed to hospital in Chilliwack.
He says it appears the fire started near the garage, but the RCMP, FortisBC and the Agassiz Fire Department are still investigating.