Calgary emergency crews respond to explosion, house fire in Marlborough

An explosion and fire at a house in Calgary on Monday prompted a sizeable and swift response from emergency crews. Firefighters were called to the 700 block Maryvale Way N.E. in the community of Marlborough at around 8:47 a.m. after area residents reported hearing a loud bang and seeing thick black smoke.  It's unknown what caused the explosion or how many people were injured.  The incident destroyed at least one home and damaged several others. Calgary police say arson investigators w