VIDEOS: A massive blaze at a two-story apartment complex sent plumes of smoke into the sky as more than 100 firefighters attempted to extinguish the flames early Wednesday morning. The Orange County Fire Authority and Tustin police responded to the intersection of Williams Street and McFadden Avenue at approximately 3 a.m. as crews encountered heavy fire coming from both floors. Firefighters went into defensive mode as a roof collapsed approximately 45 minutes after the fire erupted. At about 5 a.m., firefighters appeared to make progress on the 5-alarm blaze. At least 100 residents were displaced and two civilians suffered apparent smoke inhalation injuries considered minor. Fire officials are still in the process of confirming if everyone in the building has been accounted for.