Fire crews were sifting through the rubble of a massive building explosion in Northern California on Thursday. This is the scene in suburban San Francisco. Fire officials said the blast and resulting fire happened only hours after a construction crew damaged a gas line. At least six people were injured and taken to local hospitals. At least two nearby homes were impacted by the blast and fire. There's been an ongoing project to widen sidewalks and bike lanes in the area. #california | 23ABC Bake