Kiss nightclub fire

The Kiss nightclub fire started between 2:00 and 2:30 a.m. on 27 January 2013 in Santa Maria, Rio Grande do Sul, Brazil, killing 242 people and injuring at least 630 others. The acoustic foam in the ceiling was ignited. It was because outdoor fireworks were used indoors causing the ceiling foam to catch fire, creating a fireworks accident and nightclub fire. The premises having only one exit contributed to the high death toll as well as the electricity going out, making it impossible to find the exit with the layout the way it was. The only light in the building was coming from the bathroom where people flocked, only to be trapped with no way out as they believed it was an exit. It is the second most deadly fire in Brazilian history, surpassed only by the Niterói circus fire of 1961.

Source: Wikipedia