KINGSLEY, Iowa (AP) — A propane explosion has injured two people in northwestern Iowa and destroyed four rural buildings. Kingsley Fire Chief Paul Huth tells the Sioux City Journal that crews were called to the explosion at a hog farm near Kingsley before 7 a.m. Friday.

Huth says the explosion happened when two men walked into a hog nursery building on the property. Huth says a propane leak inside the building likely touched-off the explosion and resulting fire when door was opened, kicking on an automatic heater. The blasted severely injured the two men, who were taken to a Sioux City hospital. Their condition was not known Friday afternoon.

Authorities say the four destroyed buildings were empty, and no hogs were killed.