My girlfriend and I live on the 17th floor of 1 Canyon Avenue, near Bathurst and Sheppard apartment facing this mornings explosion. We were up watching TV at around 3:45 when we heard a thundering sound, felt our windows tremble and the building shake from where we sat. My girlfriend, Lisanne, said ``That isnt thunder`` and we both got up to look out the balcony window. We were completely shocked to see a huge pillar of fire that appeared to be 10-20 stories tall, and a black cloud of smoke that spanned the sky eastward toward Earl Bales park.  My mind raced in a panic to understand what was happening. It looked as though a plane had crashed or a bomb had fallen. Could it be a terrorist attack? After a few minutes of watching, we were completely shocked to witness an amazing mushroom cloud explosion of flame and black smoke that terrified us entirely.  I have never seen anything like it. It was so loud and big that for a moment I thought it was a nuclear explosion. For the next hour or so, we heard and saw a series of explosions, each with enough force to shake our windows. The fire seemed to get bigger for some time and at one moment we saw a flaming piece shoot out some 50 yards or so, although it is hard to tell exactly how far since we are situated a major intersection away. We did see a spectacular show of explosions, and sparks coming from the scene. We saw emergency vehicles coming from all sorts of directions, and two hours later it seemed to subside. By sunrise, the fire seemed to be mostly contained.