Fire investigation reports from the N.W.T. fire marshal's office, obtained through an access to information request, show the properties in Yellowknife and Hay River both had work done to their propane systems for which the necessary permits and inspections were not carried out.
The specific cause hasn't yet been confirmed, and the Office of the Fire Marshal is investigating. The explosion, which happened at about 10:20 a.m. Saturday, blew out the windows of nearby homes and sent a thick plume of black smoke skyward.