Nine people were injured, including two firefighters, when a blaze tore through an East Harlem building early Thursday, fire officials said. The fire erupted at 29 E. 104th St.around 1:20 a.m., according to the FDNY. Residents say the fire started on the fourth floor but thick smoke from the flames rushed through the fifth and sixth floor hallways, overwhelming anyone who tried to escape. "We were trapped," Rosa Nagovich, who lives on the fifth floor, said. "Every time we opened the door to get out there was too much smoke pouring in. It was getting worse and worse."