LONDON, ONT. -- Three people were injured after an explosion in Grey Highlands last week.

It happened April 13 around 8:46 a.m. at a rural property on Grey Road 12, near Sideroad 10A.

Police say a leak in a propane canister inside a tractor trailer caused the explosion and fire.

Three people that were working to unload the truck suffered non life-threatening burns.

The Ontario Fire Marshal and the Ministry of Labour, as well as Transport Canada were called in to help with the investigation that remains open.