A 22-year-old Hillman man was killed in an explosion on Friday.
It happened at a home in Wellington Township.
Michigan State Police said he was loading a wood boiler in the attached garage when the explosion happened.
Three of the four garage walls were destroyed.
Michigan State Police said a 46-year-old female was taken to Alpena Regional Medical Center and then airlifted to Saginaw for treatment.
She is in critical condition.
Two other females, 23 and 19, were at the home with an infant. They were treated at the scene and released.
The cause of the explosion remains under investigation.