Building a fence or planting a tree may seem like harmless home projects, but without taking one crucial step you could lose your home, and maybe, your life. Erica Johnson digs up the dirt on how powerful gas explosions can easily be prevented, but Canadians lag behind when it comes to underground warning signals. Using hidden cameras, Marketplace brings in several contractors to build a fence over an unseen gas line, and the results of the investigation are potentially explosive. Find out what you can do to stay safe.