By JULIANA BARBASSASANTA MARIA, Brazil (AP) â¿¿ There was no alarm, no working fire extinguisher, no sprinkler and almost no escape from the nightclub that became a death trap for more than 200 Brazilian college students. As investigators began poking through the rubble and families mourned their dead, the university city in southern Brazil tried to understand how the Sunday morning blaze that killed 231 people could have been sparked in the first place, then rage rapidly out of control. Why was there only one door available for exit and entry? What was the flammable material in the ceiling that allowed the conflagration to move so quickly? And, more pointedly, why was a band playing at the club allowed to use pyrotechnics inside the building? Police were leaning toward the pyrotechnics as the cause of the blaze during a party at the Kiss nightclub organized by several academic departments at the Federal University of Santa Maria. Inspector Antonio Firmino, part of the team investigating the fire, said it appeared the club's ceiling was covered with an insulating foam made from a combustible material that ignited with the pyrotechnics. Firmino said the number and state of the exits is under investigation but that it appeared that a second door was "inadequate," as it was small and protected by bars that wouldn't open. The disaster, the worst fire of its kind in more than a decade, also raises questions of whether Brazilian authorities are up to the task of ensuring safety in such venues as it prepares to host next year's World Cup and the 2016 Olympics. Some critics have said conditions in many Brazilian bars and clubs are ripe for another deadly blaze. They say that in addition to modernizing sometimes outdated safety codes and ensuring sufficient inspectors, people must change their way of thinking and respect safety regulations.