Thursday afternoon, many civilians heard a loud explosion on New York City's 121 2nd Avenue. The building, a five-story apartment complex, had caught on fire and it spread to four neighboring buildings. As firefighters were putting it out, the building collapsed.

Many people were covered in dust, and some even had bloody faces. As of Friday morning, 19 people are reported injured, four of them in critical condition. One person, 23-year-old Nicholas Figueroa is reported to be missing.

Mayor Bill de Blasio said in a statement that the explosion had been caused by a gas leak, according to the preliminary report.

Workers from the utility Consolidated Edison were at the building an hour before the explosion, checking for a planned meter installation. However, the word done there had proved to be not beneficial for the company and the workers left.

Michael S. Clendenin, a Con Edison spokesman, said that several buildings, including the one that had collapsed, had been doing renovations for the past several months, dating back to August of last year.

Civilians were in shock even hours after the explosion. Many were helping each other out, pulling debris off of each other and helping those trapped inside the building. One woman had been stuck on the fire escape and a few passersby helped her get down.

According to ABC, 250 firefighters responded to the call, and at times, the flames were so hot, that they couldn't get close enough. They continued to douse water over the neighboring buildings well into the night. Four of them were transported to hospitals with minor injuries from the fire.

Mayor de Blasio reported that they will continue to investigate and give a full report on this latest accident in the weeks to follow.